Development of a Flexible Metamaterial Film with High EM Wave Absorptivity by Numerical and Experimental Methods

The present study is intended to develop and test a cost-effective and efficient printing method for fabricating flexible metamaterial film with high electromagnetic wave absorptivity. The film can be easily applied to the surfaces with curved aspects. Firstly, numerical parametric study of the absorption characteristics of the film is performed for the range of frequency varying from 2.0 to 9.0 GHz based on commercial software package. Secondly, the flexible metamaterial films are fabricated, and experiments are conducted. The flexible metamaterial film consists of a flexible dielectric film made of polyimide (PI) and an array of split-ring resonators. The split-ring resonators of different geometric dimensions are fabricated on the PI film surface by using a silver nanoparticles ink jet printer. The performance of the flexible structure is then measured and dependence of operation frequency with higher absorptivity on the dimensions of the split-ring resonators is investigated. A comparison between the numerical and experimental data shows that the numerical predictions of the operation frequency with higher absorptivity closely agree with the experimental data.     

Al2O3-Coated Si-Alloy Prepared by Atomic Layer Deposition as Anodes for Lithium-Ion Batteries

Silicon-based anodes can increase the energy density of Li-ion batteries (LIBs) owing to their large weights and volumetric capacities. However, repeated charging and discharging can rapidly deteriorate the electrochemical properties because of a large volume change in the electrode. In this study, a commercial Fe-Si powder was coated with Al₂O₃ layers of different thicknesses via atomic layer deposition (ALD) to prevent the volume expansion of Si and suppress the formation of crack-induced solid electrolyte interfaces. The Al₂O₃ content was controlled by adjusting the trimethyl aluminum exposure time, and higher Al₂O₃ contents significantly improved the electrochemical properties. In 300 cycles, the capacity retention rate of a pouch full-cell containing the fabricated anodes increased from 69.8% to 72.3% and 79.1% depending on the Al₂O₃ content. The powder characterization and coin and pouch cell cycle evaluation results confirmed the formation of an Al₂O₃ layer on the powder surface. Furthermore, the expansion rate observed during the charging/discharging of the pouch cell indicated that the deposited layer suppressed the powder expansion and improved the cell stability. Thus, the performance of an LIB containing Si-alloy anodes can be improved by coating an ALD-synthesized protective Al₂O₃ layer.     

Study on the Polycrystalline Mechanism of Polycrystalline Diamond Synthesized from Graphite by Direct Detonation Method

In this paper, a polycrystalline diamond was synthesized by the direct detonation method using graphite as the carbon source. By comparing the numbers of the obtained diamond particles and the original graphite particles, it was found that when the graphite phase transformed into the polycrystalline diamond during the detonation process, a single graphite particle would form multiple diamond nuclei, and the nuclei would grow simultaneously to form polycrystals. Accordingly, a validation experiment was designed, which added different ratios of inert additives while keeping the ratio of graphite to hexogen (RDX) unchanged. It was found that increasing the ratio of inert additives within a certain range could increase the grain size of a polycrystalline diamond, which is consistent with the obtained polycrystalline mechanism.     

Amorphous FeCoCrSiB Ribbons with Tailored Anisotropy for the Development of Magnetic Elements for High Frequency Applications

The ferromagnetic resonance (FMR) in the frequency range of 0.5 to 12.5 GHz has been investigated as a function of external magnetic field for rapidly quenched Fe₃Co₆₇Cr₃Si₁₅B₁₂ amorphous ribbons with different features of the effective magnetic anisotropy. Three states of the ribbons were considered: as-quenched without any treatment; after relaxation annealing without stress at the temperature of 350 °C during 1 h; and after annealing under specific stress of 230 MPa at the temperature of 350 °C during 1 h. For FMR measurements, we adapted a technique previously proposed and tested for the case of microwires. Here, amorphous ribbons were studied using the sample holder based on a commercial SMA connector. On the basis of the measurements of the reflection coefficient S_11, the total impedance including its real and imaginary components was determined to be in the frequency range of 0.5 to 12.5 GHz. In order to confirm the validity of the proposed technique, FMR was also measured by the certified cavity perturbation technique using a commercial Bruker spectrometer operating at X-band frequency of 9.39 GHz. As part of the characterization of the ribbons used for microwave measurements, comparative analysis was performed of X-ray diffraction, optical microscopy, transmission electron microscopy, inductive magnetic hysteresis loops, vibrating sample magnetometry, magneto-optical Kerr effect (including magnetic domains) and magnetoimpedance data for of all samples.     

The Effect of Pore Structure on Impact Behavior of Concrete Hollow Brick,Autoclaved Aerated Concrete and Foamed Concrete

Porous concrete is an energy absorption material, which has been widely used in civil engineering, traffic engineering and disaster reduction engineering. However, the effect of pore structure on the impact behavior of the porous concrete is lacked. In this study, a series of drop-weight impact tests were carried out on three typical types of porous concrete, i.e., concrete hollow brick (CHB), autoclaved aerated concrete (AAC) and foamed concrete (FC), to investigate the effect of pore structures on their impact behavior. For comparison, static load tests were also conducted as references. According to the damage to the samples, the developments of impact force, strain, contact stress–strain relationship and absorbed energy during drop-weight during the impact test were measured and analyzed. The results show that the ratio between the peak impact stress and compressive strength of CHB was 0.44, while that of AAC and FC increased to about 0.6, indicating that the small and uniform pore structure in AAC and FC had a higher resistance against impact load than the hollow cavity of CHB. In addition, the elastic recovery strain in AAC increased by about 0.2% and its strain at peak contact stress increased by about 160% for a comparison of CHB, implying that a small open pore structure could enhance ductility. Besides, the peak contact stress of FC was close to that of AAC during impact loading, while the strain at peak contact stress of FC increased by about 36% compared with AAC, revealing that the closed-pore structure could further enhance the deformation potential. Correspondingly, the energy absorption rates of CHB, AAC and FC were 85.9 kJ/s, 54.4 kJ/s and 49.7 kJ/s, respectively, where AAC decreased by about 58% compared with CHB, and FC decreased by about 10% compared with AAC.     

纳米喷雾干燥技术用于生地黄低聚糖微粉的制备工艺研究

目的采用纳米喷雾干燥技术制备载药量高、收率高、吸湿性好的生地黄低聚糖微粉。方法采用B-90纳米喷雾干燥仪制备生地黄低聚糖微粉,采用单因素试验考察后,通过正交试验设计,以平均粒径、收率和吸湿率为评价指标,考察进风口温度、喷雾干燥效率和药液质量分数对制备工艺的影响并优选最佳制备工艺。结果正交试验结果得到最佳制备工艺条件:进风口温度为110℃、喷雾干燥效率为50%、药液质量分数为1.0%,最终得到了载药量为30%、收率为89%、吸湿性良好的生地黄低聚糖微粉,微粉形态稳定。结论采用纳米喷雾干燥技术制备生地黄低聚糖的工艺稳定可行,得到的微粉质量良好,优于传统的喷雾干燥。     

生物分配胶束色谱法预测中药制剂消炎利胆片膜通透性的研究

目的:基于生物分配胶束色谱法进行复杂中药制剂消炎利胆片的分离和膜通透性预测。方法:考察了生物分配胶束色谱的保留因子与药物膜通透性的相关性,以非离子型表面活性剂Brij 35作为流动相,模拟生物体内环境,得到各受试药物的保留因子Log k,与膜通透性参数(口服吸收率、Log Papp、Log BB)数据进行相关分析得出定量保留-膜通透性(QRPR)模型。结果:预测了消炎利胆片10个主要保留成分的透膜吸收情况。结论:生物分配胶束色谱可以用于中药复杂成分的分离,以及预测药物主成分的透膜吸收活性。     

Transplacental passage of Pt after treatment with the new triamine complex cis-diaminechloro-[2-(diethylamino) ethyl 4-amino-benzoate,N<Superscript>4</Superscript>]-chloride platinum (II) monohydrochloride monohydrate

Cis-diaminechloro-[2-(diethylamino) ethyl 4-amino-benzoate, N⁴]-chloride platinum (II) monohydrochloride monohydrate (DPR) is a monofunctional Pt triamine complex synthesized starting from cisplatin and procaine hydrochloride, characterized by a good antitumor activity coupled with low toxic effects and able to impair prenatal development of mice but at doses outside or just in the upper range of therapeutic doses. In the present paper the transplacental passage of DPR-derived Pt was investigated in CD1 mice on days 9, 13, 16 and 18 of pregnancy, 24 h after ip administration of 21 mg/kg DPR. For comparison, groups of mice were treated with an equivalent Pt-containing dose of cisplatin (10.7 mg/kg). Similarly to cisplatin, small amounts of Pt were detected in fetuses on day 9. From day 13 of gestation the concentration of DPR- and cisplatin-derived Pt increased up to the highest fetal concentrations detected on day 16. On day 18 the concentration of Pt decreased. Most importantly, on days 13–18 of pregnancy cisplatin-derived Pt was always significantly higher than that assayed after DPR administration. In addition, on day 13 of pregnancy Pt exposure of fetuses was significantly higher when dams were treated with cisplatin (AUC_0.5–24= 3.40 vs. 4.95 g·h/g). Finally, it is worth noting that serum decay of Pt after DPR or cisplatin administration in adult female mice was similar with AUC_0.13–2h s of 7.5 and 6.6 g·h/ml, respectively. When we determined the concentration of Pt into the main organs of fetuses from dams treated with either DPR or cisplatin on day 18 of gestation, we observed a different organ distribution. In fact, while the concentration of DPR-derived Pt was greater in the heart (1.08±0.30 vs. 0.78±0.35 g/g, p <0.10), an opposite situation was found in the kidney (0.51±0.20 vs. 0.69±0.22 g/g, p <0.05). In conclusion, our data show that DPR may pass through the placenta with an efficiency significantly lower than that of cisplatin. This finding may represent one of the possible causes of the lower embryotoxic/teratogenic effect of DPR as compared to cisplatin.     

Dietary Fibre and Organic Acids in Kiwifruit Suppress Glycaemic Response Equally by Delaying Absorption—A Randomised Crossover Human Trial with Parallel Analysis of 13C-Acetate Uptake

Non-sugar components of kiwifruit reduce the amplitude of the glycaemic response to co-consumed cereal starch. We determined the relative contribution of different non-sugar kiwifruit components to this anti-glycaemic effect. Healthy participants (n = 9) ingested equal carbohydrate meals containing 20 g starch as wheat biscuit (WB, 30 g), and the sugar equivalent of two kiwifruit (KFsug, 20.4 g), either intrinsic or added as glucose, fructose and sucrose (2:2:1). The meals were WB+KFsug (control, no non-sugar kiwifruit components), WB + whole kiwifruit pulp (WB+KF), WB + neutralised kiwifruit pulp (WB+KFneut), WB + low-fibre kiwifruit juice (WB+KFjuice) and WB+KFsug + kiwifruit organic acids (WB+KFsug+OA). All meals were spiked with 100 mg sodium [1-¹³C] acetate to measure intestinal absorption. Each participant ingested all meals in random order. Blood glucose and breath ¹³CO₂ were measured at ingestion and at 15 min intervals up to 180 min. Compared with WB+KFsug, whole kiwifruit pulp (WB+KF) almost halved glycaemic response amplitude (p < 0.001), reduced incremental area under the blood glucose response curve (iAUC) at 30 min (peak) by 50% (p < 0.001), and averted late postprandial hypoglycaemia. All other treatments suppressed response amplitude half as much as whole kiwifruit and averted acute hypoglycaemia, with little effect on iAUC. Effects on ¹³CO₂ exhalation paralleled effects on blood glucose (R² = 0.97). Dietary fibre and organic acids contributed equally to the anti-glycaemic effect of kiwifruit by reducing intestinal absorption rate. Kiwifruit flesh effectively attenuates glycaemic response in carbohydrate exchange, as it contains fructose, dietary fibre and organic acids.     

氢溴酸高乌甲素大鼠在体胃肠的吸收动力学研究

 目的：考察氢溴酸高乌甲素(LH)在大鼠胃肠道的吸收动力学特征及促进剂对其的吸收促进效果。方法：采用大鼠在体胃肠吸收实验模型,用HPLC法测定循环液中药物的浓度。结果：LH在胃、十二指肠、空肠、回肠、结肠的吸收百分率分别为9.67%,19.61%,11.83%,12.95%,9.51%;不同质量浓度的LH(10～40 mg?L-1)与小肠吸收量呈线性关系,吸收速率常数Ka几乎不变。P-糖蛋白抑制剂维拉帕米可增加药物从小肠的吸收。促进剂对药物在小肠内的吸收促进效果均比较明显,癸酸钠吸收促进效果最好。组织病理学观察结果显示,癸酸钠对小肠黏膜造成的损伤最小。结论：药物在整个胃肠道中的吸收均比较有限,在小肠中的吸收呈一级动力学过程,吸收机制有可能为被动扩散;吸收促进剂癸酸钠吸收促进效果最好,且毒性最小,有望作为药用辅料用于口服制剂中提高LH的生物利用度。