With vitamin A acetate as raw material, ethylenediamine retinyl Schiff base salts coordinated with rare earth ion La3+, Ce3+ were synthesized, and the structure of the products was characterized by ...FT-IR and Raman spectra. The electromagnetic parameters in the frequency range of 2-18 GHz were measured by microwave vector network analyzer, its reflectivity was calculated, and the main factors and mechanism that affect the wave-absorbing performance of rare retinyl Schiff base salts were discussed. The results show that the coordination bond is formed by the rare earth ions and Schiff base. The reflectivity of Schiff base coordinated with La3+ ion is -16 dB at 12.9 GHz (bandwidth with reflectivity better than -10 dB is 3.1 GHz), the reflectivity of Schiff base coordinated with Ce3+ ion is -18.8 dB at 12.7 GHz (bandwidth with reflectivity better than -10 dB is 3.4 GHz). Microwave absorption performances of the both are superior to the wave-absorbing performance of Schiff base coordinated with non-rare earth ions
With vitamin A acetate as raw material, ethylenediamine retinyl Schiff base salts coordinated with rare earth ion La3+, Ce3+ were synthesized, and the structure of the products was characterized by ...FT-IR and Raman spectra. The electromagnetic parameters in the frequency range of 2-18 GHz were measured by microwave vector network analyzer, its reflectivity was calculated, and the main factors and mechanism that affect the wave-absorbing performance of rare retinyl Schiff base salts were discussed. The results show that the coordination bond is formed by the rare earth ions and Schiff base. The reflectivity of Schiff base coordinated with La3+ ion is –16 dB at 12.9 GHz (bandwidth with reflectivity better than –10 dB is 3.1 GHz), the reflectivity of Schiff base coordinated with Ce 3+ ion is –18.8 dB at 12.7 GHz (bandwidth with reflectivity better than –10 dB is 3.4 GHz). Microwave absorption performances of the both are superior to the wave-absorbing performance of Schiff base coordinated with non-rare earth ion
Hierarchically porous SiO
2
/C hollow microspheres (HPSCHMs) were synthesized by a hydrothermal and NaOH-etching combined route. The adsorption performance of the prepared HPSCHMs was investigated to ...remove Congo Red (CR) in aqueous solution. The results show that the synthesized composite possesses a hollow microspherical structure with hierarchical pores and a diameter of about 100-200 nm, and its surface area is up to 1154 m
2
g
−1
. This material exhibits a remarkable adsorption performance for CR in solution, and its maximum adsorption amount for CR can reach up to 2512 mg g
−1
. It shows faster adsorption and much higher adsorption capacity than the commercial AC and γ-Al
2
O
3
samples under the same conditions. The studies of the kinetics and thermodynamics indicate that the adsorption of CR on the PHSCHM sample obeys the pseudo-second order model well and belongs to physisorption. The adsorption activation energy is about 7.72 kJ mol
−1
. In view of the hierarchically meso-macroporous structure, large surface area and pore volume, the HPSCHM material could be a promising adsorbent for removal of pollutants, and it could also be used as a catalyst support.
Hierarchically porous SiO
2
/C hollow microspheres (HPSCHMs) were synthesized. Its surface area is up to 1154 m
2
g
-1
. Hierarchically porous structure facilitates diffusion of adsorbate. Its maximum adsorption amount for Congo Red is up to 2512 mg g
-1
.
Multiple-input-multiple-output (MIMO) based on energy detection has the advantages of being insensitive to Doppler shift and low complexity. However, the square-law processing causes the nonlinear ...mutual interference of MIMO spatial-multiplexing signal detection. In this paper, linear and nonlinear detections are derived for spatial-multiplexing based MIMO multi-level amplitude-shift keying (MIMO-MASK) modulation. The linear low-complexity detection is based on the equivalent linear model with the complementary amplitude waveform and the energy difference operation at receiver; The other nonlinear detection using deep neural network is theoretically analyzed to be suitable for the nonlinear model of mutual interference. The former requires estimation of real channel information, while the latter does not require pre-estimation of channel information but requires supervised network training. The performances of both detection algorithms are verified by simulations, and both of them are insensitive to Doppler shift.
An ultra-compact silicon polarization rotator based on inverse-designed subwavelength structures is proposed and experimentally exhibited high performance with high extinction ratio of 19 dB, a ...footprint of 1.2 × 7.2 μm 2 and only one-step etching.
【摘要】 基质金属蛋白酶9（matrix metalloproteinases 9，MMP9）被证明在缺血性卒中患者梗死灶及梗死灶周围脑组织，梗死灶血管周围及外周血中性粒细胞中均高表达。聚合酶δ-相互作用蛋白2、白细胞介素17（interleukin17，IL-17）、肿瘤坏死因子α、IL-1β、心血管活性肽、血管内皮生长因子等可通过p38丝裂原活化蛋白激酶（mitogen activated ...protein kinases，MAPK）、细胞外调节蛋白激酶1/2依赖的核因子κB（nuclear factor κB，NF-κB）和活化蛋白-1、p42/p44MAPK、c-Jun氨基末端激酶、p65-NF-κB等不同途径促进MMP9的表达。MMP9的高表达与缺血性卒中出血转化关系密切，且外周血MMP9水平变化与rt-PA溶栓患者死亡或症状性颅内出血独立相关，与缺血性卒中严重程度及不良功能结局相关。MMP9 rs3918242位点基因多态性与缺血性卒中的风险及疾病严重程度可能相关，但目前研究的结果和结论尚不一致。 【Abstract】 When ischemic stroke occurs, matrix metalloproteinases 9 (MMP9) has been shown to be highly expressed in infarct lesion and surrounding cerebral tissue, and neutrophils will be highly expressed in perivascular around infarct focus and peripheral blood. Polymerase δ-interacting protein 2, interleukin17 (IL-17), tumor necrosis factor alpha, IL-1β, cardiovascular active peptide, vascular endothelial growth factor may promote the expression of MMP9 through p38 mitogen activated protein kinases (MAPK), extracellular regulated protein kinases 1/2-depen
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