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1.
Micron-sized silica gel particles were first surface-modified with coupling agent, γ-methacryloylpropyl trimethoxysilane (MPS), and the polymerizable double bonds were introduced onto the surfaces of silica gel particles, forming the modified particles MPS-SiO2. Subsequently, N,N-dimethylaminoethyl methacrylate (DMAEMA) was graft-polymerized on the surfaces of particles MPS-SiO2 in the manner of “grafting through”, resulting in the grafted particles PDMAEMA/SiO2. The grafted particles PDMAEMA/SiO2 were fully characterized with several means. The graft polymerization process of DMAEMA on particles MPS-SiO2 was studied in detail, and the optimal reaction conditions were determined. Thereafter, the adsorption properties of the grafted particles PDMAEMA/SiO2 for chromate anion and Cu2+ ion were preliminarily examined respectively. The experimental results indicate that the PDMAEMA grafting degree on PDMAEMA/SiO2 particles is limited because an enwinding polymer layer as a kinetic barrier on the surfaces of silica gel particles will be formed during the graft polymerization, and blocks the graft polymerization. In order to enhance PDMAEMA grafting degree, reaction time and temperature, and the used amount of initiator as well as the monomer concentration should be effectively controlled. The preliminary adsorption tests show that the grafted particles PDMAEMA/SiO2 are multi-functional. They possess very strong adsorption ability for CrO42− anion by right of strong electrostatic interaction, and have also adsorption action towards heavy metal ion by dint of complexing action.  相似文献   
2.
The laser-induced damage characteristics and adsorption effects of organic contamination molecules of two high reflectors (HR) prepared by electron beam evaporation (EB) and ion beam sputtering (IBS) method at 1064 nm is investigated in vacuum. It is found that EB films show the performance degradation of laser induced damages in vacuum while for IBS film, seems to have no this effect, in comparison with air environment. In addition, EB coatings also have the strong affinity with organic contamination molecules, in contrast of IBS films. The results reveal that ion beam sputtering (IBS) method seem to be one of the favorite film deposition techniques of the optical films used in vacuum and space environments.  相似文献   
3.
When designing and modeling metal vapor and metal halide vapor lasers, the radial distribution of the gas temperature is found by solving the steady-state heat conduction equation for the internal tube at mixed boundary conditions. The volume power density is usually taken as a constant and the unknown value for the temperature of the inner wall is substituted by the measured temperature of the outer wall of the composite laser tube. In this paper, these inaccuracies are overcome. A general solution of the steady-state heat conduction problem has been suggested for an arbitrary volume power density. In order to determine the temperature of the inner wall, a complete model of the radial heat flow has been constructed. The resulting model has been applied in order to evaluate the gas temperature of a new high-powered strontium laser at different qualitative distributions of volume power density. The results have been compared with the known simple models. The presented model could be used on its own for existing and future lasers or as part of other types of theoretical or computer models.  相似文献   
4.
It is known that natural systems are undeniably subject to random fluctuations, arising from either environmental variability or internal effects. In this paper, a spatial version of an epidemic model which contains some important factors, such as noise on the infective and diffusion processes on both the susceptible and infective, is investigated. From the numerical results, we know that noise can induce instability and enhance the oscillation of the species density and the cooperation between noise and diffusion gives rise to the appearance of a rich transport phenomenology. Our results show that noise can play a prominent role in the spatial epidemic model.  相似文献   
5.
铜(Cu)含量的高低直接影响着生命体的正常运转和自然体系的平衡.检测铜离子的方法多种多样,其中具有较高敏感度和选择性的荧光化学传感器应用更加广泛.综述了以Cu^2+为基的荧光化学传感器通过替换法实现了对阴离子S^2-, CN^-, H2PO4^-, PPi和I^-以及中性分子ATP、ADP和生物硫醇等的连续识别的研究进展.  相似文献   
6.
A titanocene-ferrocenyl complex, (5-ferrocenyl-2-hydroxybenzenecarboxylato- O,O′)-bis(methylcyclopentadienyl)titanium(IV) 4, and an unexpected ionic complex, [C7H8NO3]- [(C5H5)Fe(C5H4)SO3]·H2O3 were synthesized and characterized by IR, ^1H NMR and elemental analysis. Compound 3 is of triclinic, space group P1 with a = 5.954(2), b = 13.208(5), c = 13.252(5) A, α = 60.993(7),β = 84.342(8),γ = 86.933(8)°, Z = 2, V = 906.8(6)A^3, Dc = 1.601 g/cm^3, μ(MoKα) = 0.987 mm^-1, F(000) = 452, the final R = 0.0647 and wR = 0.1333 for 2311 observed reflections (I 〉 2σ(I)). Compound 4 belongs to the monoclinic system, space group P2 1/c with α = 14.3310(9), b = 12.5065(8), c = 12.9406(10) A, β = 95.101(4)°, Z = 4, V = 2310.2(3) A^3, Dc = 1.513 g/cm^3, μ(MoKα) = 1.004 mm^-1, F(000) = 1088, the final R = 0.0461 and wR = 0.1048 for 2112 observed reflections (1 〉 2σ(I)).  相似文献   
7.
In this study, we have successfully synthesized a novel coumarin-based dendrons derivative CD and its chemical structure was characterized by 1H NMR, 13C NMR and ESI-HR-MS. The sensor CD showed an obvious “on-off” fluorescence quenching response toward Cu2+ with a maximum quenching efficiency of 99.8%. The CD-Cu2+ complex showed an “off-on” fluorescence enhancement response toward PPi over many competitive anions. The detection limit of the sensor CD was 0.29?×?10?6?M to Cu2+ and 2.39?×?10?9?M to PPi. In addition, the sensor CD showed a 1:1 binding stoichiometry to Cu2+ and the sensor CD-Cu2+ showed a 2:1 binding stoichiometry to PPi in CH3CN/HEPES buffer medium (9:1 v/v, pH?=?7.2). The stable pH range of sensor CD to Cu2+ and CD-Cu2+ to PPi was from 3 to 8.  相似文献   
8.
9.
采用静态吸附法研究了ASA-PGMA/SiO2对稀土离子的螯合吸附性能、吸附动力学和热力学。实验结果表明,其对稀土离子的吸附能力分别为:La3+:38.6 mg.g-1,Pr3+:39.6 mg.g-1,Nd3+:41.8 mg.g-1,Sm3+:42.8 mg.g-1,Tb3+:46.2 mg.g-1。吸附等温模型符合Lang-muir型单分子层吸附。介质pH值对材料的吸附能力有很大影响,pH值为6时吸附量最大。以盐酸为洗脱剂,当酸度为0.1 mol.L-1时,洗脱率为99.8%。连续吸附-脱附实验表明,ASA-PGMA/SiO2重复使用10次后,吸附能力变化很小。  相似文献   
10.
采用分子动力学(MD)模拟方法在COMPASS力场下,研究了不同质量比(10/90,30/70,50/50,70/30和90/10)聚乳酸(PLA)/聚酰胺11(PA11)共混物的相容性.研究结果表明:不同比例下PLA/PA11共混物的Gibbs自由能变化均大于零,其共混物很难形成均相体系;共混体系结合能的计算以及不同组分分子间C—C原子对径向分布函数的分析揭示了PLA和PA11的相互作用主要源自其分子间的范德华力;此外,模拟得到的所有比例下共混物的Flory-Huggins相互作用参数(χ)均大于临界Flory-Huggins相互作用参数(χcritical),进一步证明PLA与PA11不能形成相容体系。  相似文献   
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