Preparation and characterization of an immunoaffinity chromatography column for the selective extraction of trace contraceptive drug levonorgestrel from water samples

The preparation and characterization of an immunoaffinity chromatography (IAC) column for the specific extraction and enrichment of trace contraceptive drug levonorgestrel (LNG) from water samples were described. The IAC column was constructed by covalently coupling specific polyclonal antibody against LNG to CNBr-activated Sepharose 4B and packed into a common solid phase extraction (SPE) cartridge. The extraction conditions including loading, washing and eluting solutions, as well as the effect of flow rate on the extraction were carefully optimized. Pure water, 5% of methanol and 50% of methanol were respectively selected as loading, washing and eluting solutions, while the flow rates in the loading, washing and eluting steps were selected to be 1.0, 2.0 and 0.5 mL min⁻¹, respectively. Under optimal conditions, the IAC column was characterized in terms of maximum capacity, extraction recovery and stability. It was found that, for IAC column packed with 0.2 g of solid support immobilized with antibody, the maximum capacity for LNG was about 260 ng. The extraction recoveries of the column for LNG at three different spiked concentrations were within 95.3-106.9%. After more than 35 times repeated usage, there was not significant loss of specific recognition. Using high performance liquid chromatography (HPLC) as an analytical tool, trace amount of LNG in the range of ng L⁻¹ was found in river water and wastewater samples after 600-fold enrichment, demonstrated the feasibility of the prepared IAC column for LNG extraction.     

Two novel aconane-type diterpenes derived from C-nor-C_(19)-diterpenoid alkaloid

Two novel C-nor-B-homo aconane-type diterpenes 4 and 5.featuring a unique eight-membered ring system,were obtained by the treatment of C-nor-C19-diterpenoid alkaloid 3 with HNO2 in 8%and 21%yields,respectively.Structures of these two compounds were established based on the combination of spectroscopic data,including HRESIMS,1D and 2D NMR data.A plausible mechanism for the formation of 4 and 5 is also presented.     

Poly[bis(μ3‐5′‐carboxy‐2,2′‐bipyridine‐5‐carboxylato‐κ4O:N,N′:O′)lead(II)]

The title compound, [Pb(C₁₂H₇N₂O₄)₂]_n, obtained by reaction of Pb(NO₃)₂ and 2,2′‐bipyridine‐5,5′‐dicarboxylic acid (H₂bptc) under hydrothermal conditions, has a structure in which the unique Pb^II cation sits on a twofold axis and is octa‐coordinated by four O‐atom donors from four Hbptc⁻ ligands and four N‐atom donors from two Hbptc⁻ ligands in a distorted dodecahedral geometry. With each Pb^II cation connected to six Hbptc⁻ ligands and each Hbptc⁻ ligand bridging three Pb^II cations, a three‐dimensional polymeric structure is formed. From a topological point of view, the three‐dimensional net is binodal, with six‐connected (the Pb^II cation) and three‐connected (the Hbptc⁻ ligand) nodes, resulting in a distorted rutile (4².8)₂(4⁴8⁹12²) topology.     

Compact FBG diaphragm accelerometer based on L-shaped rigid cantilever beam

A compact fiber Bragg grating(FBG) diaphragm accelerometer based on L-shaped rigid cantilever beam is proposed and experimentally demonstrated.The sensing system is based on the integration of a flat diaphragm and an L-shaped rigid cantilever beam.The FBG is pre-tensioned and the two side points are fixed,efficiently avoiding the unwanted chirp effect of grating.Dynamic vibration measurement shows that the proposed FBG diaphragm accelerometer provides a wide frequency response range(0-110 Hz) and an extremely high sensitivity(106.5 pm/g),indentifying it as a good candidate for embedding structural health monitoring and seismic wave measurement.     

A prototype RF power source for CSNS/RCS

A prototype RF power source has been built to supply high RF power to a ferrite-loaded cavity, which is a part of R&D of the Rapid Cycling Synchrotron of China Spallation Neutron Source (CSNS/RCS). A direct fast RF feedback amplifier, a 4:1 impedance transformer and auto tuning grid were locally located to compensate the heavy beam loading of CSNS/RCS. Design and commissioning of the RF power source is discussed here, also with some advice on system improvement.     

Composition-dependent phase separation effects of organic solar cells using P3HT:PCBM as active layer and chromium oxide as hole transporting layer

Phase separation of the poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) active layer (ATL) was investigated by varying their relative ratio in the organic solar cells (OSCs). With the help of the UV/visible spectrophotometer, optical microscopy and scanning electron microscope, we found that the cluster of PCBM at the interface or surface was affected by Al cathode, the composition of the blends and thermal annealing. The disc-like shape crystals of PCBM substituted for the needle-like ones at higher PCBM compositions at the ATL/Al interface, which led to stronger contacts and bigger contact area. It could make short circuit current density increase, but may affect the blend morphology and result in parallel resistance and open circuit voltage decreased with the PCBM ratio increasing from 40 to 60%. The microstructure of the P3HT:PCBM ATL, determined by the composition dependent phase separation, supported the optimized performance of the OSCs with the composition of 40-50% PCBM.     

Frequency driven scanning characteristic of a pinna model inspired from the Brown Big-eared bat（Plecotus auritus）

According to the parameters of a Brown Big-eared bat’s pinna,a simple obliquely truncated bat ear model that made by line and plane was designed,which was numerically simulated with finite element method.The change of far-field directivity was analyzed in elevation and azimuth as the frequency increased.The results show that,compared with the pinna of the Brown big-eared bat,the present model has the advantages in wider bandwidth of frequency driven scanning,better directivity in azimuth and larger angle scales in elevation. In addition,a wireless positioning method based on single base station could be achieved by using a frequency driven scanning antenna.     

Preparation and holographic storage properties of tri-doped Mg:Mn:Fe:LiNbO3 crystals

Doping MgO, MnO and Fe₂O₃ in LiNbO₃ crystals, tri-doped Mg:Mn:Fe:LiNbO₃ single crystals were prepared by the conventional Czochralski method. The UV-vis absorption spectra were measured and the shift mechanism of absorption edge was also investigated in this paper. In Mg:Mn:Fe:LiNbO₃ crystal, Mn and Fe locate at the deep level and the shallow level, respectively. The two-photon holographic storage is realized in Mg:Mn:Fe:LiNbO₃ crystals by using He-Ne laser as the light source and ultraviolet as the gating light. The results indicated that the recording time can be significantly reduced for introducing Mg²⁺ in the Mg:Mn:Fe:LiNbO₃ crystal.     

海洋大气气溶胶光学模型参数的相关性研究

气溶胶光学模型参数在气溶胶遥感和气候强迫研究中都具有重要的作用.通过对全球近90个气溶胶自动观测网(AERONET)的海洋站点数据进行筛选、分类和分析,发现了气溶胶模型的中值半径及其标准偏差间的负相关性,并给出了经验关系.利用该关系对现行中分辩率成像光谱仪(MODIS)海洋气溶胶模型进行了评估,并指出了该模型存在的不足...     

Effect of shape of Sendust particles on their electromagnetic properties within 0.1-18 GHz range

The microwave permeability dispersion behaviors and microwave-absorbing properties for different shapes of Sendust particles prepared by vibrating ball milling at 35 vol% in paraffin wax matrix have been investigated. The dispersion spectrum of permeability was calculated by the Landau-Lifshitz-Gilbert equation and Bruggeman’s effective medium theory. The calculated results are in agreement with the experiment data. According to the calculation results, the value of (μ₀−1)f_r (μ₀ is static permeability, and f_r is resonance frequency) for flake particle with larger aspect ratio reached 59.1 GHz and exceeded the Snoek’s limit. Considering the quarter-wavelength model and transmission line theory, the microwave absorption peak was discussed. At the frequency range, the flake particle with larger aspect ratio can make a thinner absorber. It provides a way to decrease layer thickness of magnetic absorber.