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71.
Four three-dimensional non-interpenetrating open coordination frameworks constructed from the CTC ligand (CTC =cis,cis-1,3,5-cyclohexanetricarboxylate) coordinated to metal ions (Mn(II) and Cd(II)): Mn(3)(CTC)(2)(DMF)(2)(1); Cd(3)(CTC)(2)(H(2)O)(3).H(2)O (2); Cd(3)(CTC)(2)(4,4'-bpy)(2)(EG)(2)(3); Cd(3)(CTC)(2)(mu(2)-hmt)(DMF)(C(2)H(5)OH)(H(2)O).2H(2)O (4)(DMF = dimethylformamide and EG = ethylene glycol) have been synthesized by slow evaporation of DMF-C(2)H(5)OH-H(2)O solutions of M(II)(Mn(II) or Cd(II)) and CTC in the presence of the organic bases TEA (triethylamine), TEA, 4,4'-bpy (4,4'-bipyridine) and hmt (hexamethylenetetramine), respectively, and structurally characterized by X-ray crystallography. The polymer constructed by CTC and Mn(II) exhibits a 3-D architecture with 5 x 9 A channels; the polymer formed by CTC and Cd(II) exists a 3-D extended framework with 9 x 9 A channels; wave-like sheet subunits of the polymer are upheld by 4,4'-bpy ligands resulting in a 3-D framework with 4 x 10 A channels; two-fold alternate sheet subunits of the polymer are interlinked by mu(2)-hmt ligands to form a novel 3-D architecture with 7 x 8 A channels. Polymers exhibit their strongest excitation peaks at 391, 390 and 394 nm, respectively, and their main strong emission peaks are at 543, 460 (with a shoulder peak at about 570 nm) and 557 nm, respectively.  相似文献   
72.
Integration between a hand-held mass spectrometry desorption probe based on picosecond infrared laser technology (PIRL-MS) and an optical surgical tracking system demonstrates in situ tissue pathology from point-sampled mass spectrometry data. Spatially encoded pathology classifications are displayed at the site of laser sampling as color-coded pixels in an augmented reality video feed of the surgical field of view. This is enabled by two-way communication between surgical navigation and mass spectrometry data analysis platforms through a custom-built interface. Performance of the system was evaluated using murine models of human cancers sampled in situ in the presence of body fluids with a technical pixel error of 1.0 ± 0.2 mm, suggesting a 84% or 92% (excluding one outlier) cancer type classification rate across different molecular models that distinguish cell-lines of each class of breast, brain, head and neck murine models. Further, through end-point immunohistochemical staining for DNA damage, cell death and neuronal viability, spatially encoded PIRL-MS sampling is shown to produce classifiable mass spectral data from living murine brain tissue, with levels of neuronal damage that are comparable to those induced by a surgical scalpel. This highlights the potential of spatially encoded PIRL-MS analysis for in vivo use during neurosurgical applications of cancer type determination or point-sampling in vivo tissue during tumor bed examination to assess cancer removal. The interface developed herein for the analysis and the display of spatially encoded PIRL-MS data can be adapted to other hand-held mass spectrometry analysis probes currently available.

Integration between a hand-held mass spectrometry desorption probe based on picosecond infrared laser technology (PIRL-MS) and an optical surgical tracking system demonstrates in situ tissue pathology from point-sampled mass spectrometry data.  相似文献   
73.
74.
刘延秋  田秋 《结构化学》1994,13(3):163-169
本文用自旋捕捉与ESR技术相结合的方法研究了ZnS胶体溶液中某些无机盐光化学过程中产生的无机阴离子自由基,并对自由基产生的机理进行了讨论  相似文献   
75.
Three new serratane triterpenoids, (3α,14α,15α,21α)‐3,14,15,21,29‐pentahydroxyserratan‐24‐oic acid ( 1 ), (3α,21β)‐serrat‐14‐ene‐3,21,24,30‐tetraol ( 2 ), and (3α,21α)‐serrat‐14‐ene‐3,21,24,29‐tetraol ( 3 ), were isolated from Phlegmariurus squarrosus, together with eight known compounds. Their chemical structures were elucidated on the basis of in‐depth spectroscopic analyses.  相似文献   
76.
Luo X  Lu Z  Xi J  Wu Z  Zhu W  Chen L  Qiu X 《The journal of physical chemistry. B》2005,109(43):20310-20314
The preparation and physical characterization of a poly(vinylidene fluoride)-graft-poly(styrene sulfonic acid) (PVDF-g-PSSA) membrane prepared by a solution-grafting method were described. These membranes exhibited high conductivity with a value 3.22 x 10(-2) S/cm at 30 degrees C. ICP studies revealed that the PVDF-g-PSSA membrane showed dramatically lower vanadium ion permeability compared to Nafion 117. Trivalent vanadium ions had the highest permeability through all these membranes in contrast to pentavalent vanadium ions with the lowest. The VRB with the low-cost PVDF-g-PSSA membrane exhibited a higher performance than that with Nafion 117 under the same operating conditions, and its energy efficiency reached 75.8% at 30 mA/cm(2). The performance of VRB with the PVDF-g-PSSA membrane can be maintained after more than 200 cycles at a current density of 60 mA/cm(2).  相似文献   
77.
运用循环伏安和阶跃电位方法研究了Ni(OH)2粉末靶直流溅射沉积的NiOxHy薄膜电致变色特性.结合实时的光透射-时间变化,发现着色后的薄膜在零外电势下有一自发的消色过程,该过程可能对应着Li 的自发注入。着色没有自发过程,获取了着消色状态Ni2p3/2和O1s的XPS谱,表明在着色态镍被氧化,消色态镍被还原,相应地氧的化学环境发生改变.  相似文献   
78.
The geometric and electronic structures of FeS(2) (100) surface have been studied by a quantum-mechanical calculation using a total-energy pseudopotential code, CASTEP. The (100) surface is very stable and does not give any significant geometric relaxation. The electronic structure of FeS(2) (100) surface is characterized by the appearance of new native surface states in the bulk band gap, which correspond to antibonding mixed Fea-Ssp(3) states. These surface states play an important role as mediators of electron transfer on both anodic and cathodic sites in the incipient oxidation of pyrite. Moreover, the (100) surface has small band gaps and shows some metallic character. It is predicted that the rate of cathodic reductive reaction of O(2) in the incipient oxidation of pyrite is much faster than previously considered. The transport of electrons from the anodic sites to the cathodic sites on the (100) surface is faster and hole injection of anodic sites is not the rate-determining step. So we can deduce that the rate-determining step of incipient oxidation for pyrite consists of both electron transfer of pyrite/aqueous O(2) interface and the splitting of H(2)O.  相似文献   
79.
Three new triterpenoids, (3β,8β,14α,21α)‐26,27‐dinoronocerane‐3,8,14,21‐tetrol ( 1 ), (3β,8β,14α,21β)‐26,27‐dinoronocerane‐3,8,14,21‐tetrol ( 2 ), and lycopodiin A ( 3 ), together with four known compounds, lycoclavanol ( 4 ), lycoclaninol ( 5 ), α‐onocerin ( 6 ), and 3‐epilycoclavanol ( 7 ), were isolated from Lycopodium japonicum Thunb (Lycopodiaceae). Their structures were established by means of spectroscopic analyses. Compounds 3 and 7 showed moderate antitumor activity. Compounds 4 and 6 exhibited acetylcholinesterase inhibition activity.  相似文献   
80.
We demonstrate a novel strategy for the preparation of mesoporous silica-supported, highly dispersed, stable metal and bimetal nanoparticles with both size and site control. The supporting mesoporous silica, functionalized by polyaminoamine (PAMAM) dendrimers, is prepared by repeated Michael addition with methyl acrylates (MA) and amidation reaction with ethylenediamine (EDA), by using aminopropyl-functionalized mesoporous silica as the starting material. The encapsulation of metal nanoparticles within the dendrimer-propagated mesoporous silica is achieved by the chemical reduction of metal-salt-impregnated dendrimer-mesoporous silica by using aqueous hydrazine. The site control of the metal or bimetal nanoparticles is accomplished by the localization of inter- or intradendrimeric nanoparticles within the mesoporous silica tunnels. The size of the encapsulated nanoparticles is controlled by their confinement to the nanocavity of the dendrimer and the mesopore. For Cu and Pd, particles locate at the lining of mesoporous tunnels, and have diameters of less than 2.0 nm. For Pd/Pt, particles locate at the middle of mesoporous tunnels and have diameters in the range of 2.0-4.2 nm. The Pd and Pd/Pt nanoparticles are very stable in air, whereas the Cu nanoparticles are stable only in an inert atmosphere.  相似文献   
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