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71.
72.
This report provided the first example of using pivot concept to prepare monolithic molecularly imprinted polymers (MIPs) with ketoprofen (KET) imprints, in which metal ions were employed as mediator between the functional monomer and the template to achieve higher fidelity of imprint. To solve metal ions in pre-polymerization system, a new ternary porogen of dimethyl sulfoxide-toluene-isooctane was developed for preparation of MIP monoliths with high porosity and good permeability. The effect of polymerization parameters such as the nature of metal ions, the ratio of template to metal ion and the degree of crosslinking, on the permeability, morphology and affinity of the metal ion mediated MIP monolith were studied. The experiments demonstrated that Ni(2+), Co(2+) and Zn(2+) can be applied as pivot to prepare KET-imprinted monolith. Relative to monolithic MIP without metal ions, all the ion-mediated macropore MIP monoliths showed enhanced permeability, capacity factor and selectivity factor. High permeability (1.06×10(-7)mm(2)) was obtained on the Co(2+)-mediated MIP monolith and great selectivity factor (3.84) was achieved on the Ni(2+)-mediated one. The stoichiometric displacement model was constructed to investigate the recognition mechanism of metal-ion mediated MIP. The results indicate that metal ion as pivot not only improves the affinity but also allows the fine-tuning on the macroporous structure of MIP monolith.  相似文献   
73.
Phytochemistry investigations on Ailanthus altissima (Mill.) Swingle, a Simaroubaceae plant that is recognized as a traditional herbal medicine, have afforded various natural products, among which C20 quassinoid is the most attractive for their significant and diverse pharmacological and biological activities. Our continuous study has led to the isolation of two novel quassinoid glycosides, named chuglycosides J and K, together with fourteen known lignans from the samara of A. altissima. The new structures were elucidated based on comprehensive spectra data analysis. All of the compounds were evaluated for their anti-tobacco mosaic virus activity, among which chuglycosides J and K exhibited inhibitory effects against the virus multiplication with half maximal inhibitory concentration (IC50) values of 56.21 ± 1.86 and 137.74 ± 3.57 μM, respectively.  相似文献   
74.
In this paper, we describe the behavior of impurity transport in the HL-2A electron cyclotron resonance heating (ECRH) L-mode plasma. The neon as a trace impurity is injected by the supersonic molecular beam injection (SMBI) technique, which is used for the first time to study the impurity transport in HL-2A. The progression of neon ions is monitored by the soft X-ray camera and bolometer arrays with good temporal and spatial resolutions. The convection and diffusion process of the neon ions are investigated with the one-dimensional impurity transport code STRAHL. The results show that the diffusion coefficient D of neon ions is a factor of four larger than the neoclassical value in the central region. The value of D is larger in the outer region of the plasma (ρ 〉 0.6) than in the central region of the plasma (ρ 〈 0.6). The convective velocity directs inwards with a value of ~-1.0 m/s in the Ohmic discharge, but it reverses to direct outwards with a value of ~ 8.0 m/s in the outer region of the plasma when ECRH is applied. The result indicates that the impurity transport is strongly enhanced with ECRH.  相似文献   
75.
A metal-organic coordination compound formulated as [Zn(pzdc)(phen)] n·nH_2O 1 (H_2pzdc=pyrazine-2,3-dicarboxylic acid,phen=1,10-phenanthroline) has been hydrothermally synthesized and structurally characterized by elemental analysis,IR,fluorescence spectrum and single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic system,space group P2_(1/n) with α=11.607(2),b=11.719(2),c=13.140(3)(A),β=110.707(3)°,V=1671.9(6)(A)~3,C_(18)H_(12)ZnN_4O_5,Mr=429.69,D_c=1.707 g/cm~3,μ(MoKα)=1.511 mm~(-1),F(000)=872,Z=4,the final R=0.0356 and wR=0.0853 for 2713 observed reflections (Ⅰ> 2σ(Ⅰ). It exhibits an interesting two-dimensional layer structure and shows yellow photoluminescent property at room temperature.  相似文献   
76.
A new dinuclear complex[Zn(dpa)(bipy)(H2O)]2(dpa=2,2'-diphenic acid,bipy=2,2'-bipyridine)1 has been hydrothermally synthesized and structurally characterized by elemental analysis,IR,fluorescence spectrum and single-crystal X-ray diffraction.The complex crystallizes in monoclinic,space group P21/c with a=10.960(2),b=9.4841(18),c=20.599(4)(A),β=104.452(3)°,V=2073.4(7)(A)3,C48H36N4O10Zn2,Mr=959.55,Dc=1.537 g/cm3,μ(MoKa)=1.225 mm-1,F(000)=984,Z=2,the final R=0.0364 and wR=0.0843 for 2788 observed reflections(I>20(I)).In the crystal structure,the zinc atom is five-coordinated with two carboxylate oxygen atoms from different dpas,one coordinated water molecule and two nitrogen atoms from bipy ligands,showing a slightly distorted triangular bipyramidal geometry.Furthermore,it exhibits a zero-dimensional network structure with a sixteen-membered ring and shows yellow photoluminescent property at room temperature.  相似文献   
77.
A metal-organic coordination polymer [Zn2(pzdc)(im)3]n(H2pzdc=pyrazine-2,3-dicarboxylic acid,im= imidazole) 1 has been hydrothermally synthesized and characterized by elemental analysis,IR,fluorescence spectrum and single-crystal X-ray diffraction.Pale yellow crystals crystallize in the monoclinic system,space group P21/c,a=1.364 87(15) nm,b=1.389 43(15) nm,c=0.956 89(10) nm,β=102.354(2)°,V=1.772 6(3) nm3,C15H12N8O4Zn2,Mr=499.07,Dc=1.870 g·cm-3,F(000)=1 000,Z=4,μ(Mo Kα)=2.750 mm-1,the final R=0.032 2 and wR=0.087 8 for 3 208 observed reflections(I2σ(I)).1 shows green photoluminescent property at room temperature.  相似文献   
78.
HL-2A装置边缘等离子体测地声模带状流的三维特征采用外中平面上三组三台阶探针阵列组成具有环向、极向和径向分辨的独特结构的探针系统进行了研究.其中两组具有极向距离为65mm的三台阶5探针阵列组成极向带状流10探针组,另一组电动式带状流6探针阵列与带状流10探针组之间的环向距离为800mm. 此外,采用快速往复气动6探针组研究了磁分界面附近的温度、密度、雷诺协强及其径向分布.在HL-2A装置上同时观测到测地声模带状流(频率f=7kHz)的极向和环向对称性(m≈0,n 关键词: 三台阶式ZF探针 带状流 三维空间结构  相似文献   
79.
Two high performance silicon drift detectors (SDD) are installed at the equatorial port with z = 0 and z = -16.4 cm on HL-2A tokamak, respectively. These SDDs combine with the new and non-conventional software pulse height analyser (SPHA ) successfully developed more recently by us to measure the time evolution of soft x-rays spectra, the thermal and superthermal electron temperatures. The high-quality three-dimensional figure of time evolution for soft x-rays energy spectra is easily obtained by combination of a new SPHA and computer. Therefore, the measurement accuracies and the time resolutions of thermal and superthermal electron temperatures are also improved. The enhancement phenomenon of superthermal electron during electron cyclotron resonance heating (ECRH) can be explained by the combination of superthermal electron avalanche theory and experimental parameters.  相似文献   
80.
Using molecular statistics simulations based on the embedded atom method potential, we investigate the reliability of the lateral manipulation of single Pt adatom on Pt(111) surface with a single-atom tip for different tip heights (tip-surface distance) and tip orientations. In the higher tip-height range, tip orientation has little influence on the reliability of the manipulation, and there is an optimal manipulation reliability in this range. In the lower tip- height range the reliability is sensitive to the tip orientation, suggesting that we can obtain a better manipulation reliability with a proper tip orientation. These results can also be extended to the lateral manipulation of Pd adatom on P d (111) surface.  相似文献   
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