Transmittance and cathodoluminescence of AlN ceramics sintered with Ca3Al2O6 as sintering additive

Aluminum nitride ceramics were prepared by sintering with 0–4.8 mass% of Ca₃Al₂O₆ (C₃A) as a sintering additive. The transmittance in the range of 260–550 nm increased with increasing amount of C₃A. The cathodoluminescence intensity attributed to oxygen-induced defects decreased with increasing amount of C₃A. From the results, the increase of the transmittance in the range of 260–550 nm was considered to be related to the decrease of the oxygen-induced defect density.     

Gelling of alginate fibres

Equipment was developed to measure the time for complete gelling of sodium alginate fibres in calcium chloride solution, taken as the time to achieve maximum tensile strength. The effects of fibre diameter, alginate concentration, alginate composition and calcium chloride concentration on gelling time were investigated. A diffusional model, developed to predict the gelling time, agreed with experimental results except for the effect of calcium ion concentration which was modelled empirically.     

The low-temperature oxidation of calcium by water vapor

The oxidation kinetics of calcium in water vapor have been studied over the temperature range 25–300°C. There is a change in the form of the oxidation kinetics with temperature, from essentially linear at temperatures below 150°C to logarithmic at 300°C. This is coupled with a change in the manner of growth of the oxide layer as well as the chemical composition of the reaction product. In addition, the oxidation rate decreases with temperature, reaching a minimum at about 150°C. At temperatures below 150°C oxidation appears to be a result of the formation of cracks or fissures in the oxide film. Above 150°C no single oxidation mechanism can be deduced.     

LF精炼过程中炉渣成分对钢水[Ca]含量的影响

根据冶金熔体的共存理论,计算了CaO-MgO-MnO-FeO-SiO2-Al2O3六元渣系各组元的作用浓度。结合生产实际数据,建立了LF精炼过程中炉渣成分和钢水[Ca]之间氧化还原反应的数学模型,计算了炉渣成分对钢水[Ca]含量的影响。结果表明,LF精炼过程中钢水[Ca]含量受[Si]-(FeO)联合控制,渣中SiO2、FeO质量分数每增加1%,[Ca]质量分数分别降低1.63×10-6和1.55×10-6。为了将[Ca]质量分数控制在10×10-6以下,当FeO质量分数为3%左右时,碱度B应不高于0.9。     

pH-sensitive sodium alginate/calcined hydrotalcite hybrid beads for controlled release of diclofenac sodium

Objective: The aim of this study was to prepare pH-sensitive sodium alginate/calcined hydrotalcite (SA/CHT) hybrid bead with improved the burst release effect of the drug.

Materials and methods: A series of pH-sensitive SA/CHT hybrid beads were prepared by using Ca²⁺ cross-linking in the presence of diclofenac sodium (DS) and SA. The structure and drug loading of the beads were characterized by Fourier transform infrared spectroscopy and X-ray diffraction. The swelling and the drug release of the fabricated beads were investigated by the pH of test medium and CHT content.

Result: The formed positively charged hydrotalcite layers were adsorbed on the negatively charged SA polymer chains through electrostatic interaction and act as inorganic cross-linkers in the three-dimensional network. Compared to pure SA beads, the incorporation of CHT enhanced the drug encapsulation efficiency, improved the swelling behaviors and slowed the drug release from the hybrid beads.

Discussion and conclusions: The electrostatic interaction between hydrotalcite and SA has restricted the movability of the SA polymer chains, and then slowed down swelling and dissolution rates in aqueous solutions. The results provided a simple method to moderate drug release and matrix degradation of the SA beads.     

海藻酸纤维对Zn2+的吸附性能研究

研究了海藻酸纤维对Zn2+的吸附性能,对Zn2+浓度、温度、时间以及pH值等影响因素进行了分析。结果表明:吸附时间和温度对吸附平衡的影响较小,但Zn2+溶液的初始浓度和pH值的影响很大。初始浓度越大,吸附容量越大但去除率越小,pH值在5～7时去除率较大。Freundlich吸附模型比Lang-muir吸附模型能更好地模拟海藻酸纤维对Zn2+的吸附过程。     

Recent Advances in Calcium-Based Anticancer Nanomaterials Exploiting Calcium Overload to Trigger Cell Apoptosis

Calcium ion is vital for the regulation of many cellular functions and serves as a second messenger in the signal transduction pathways. Once the intracellular Ca²⁺ level exceeds the tolerance of cells (called Ca²⁺ overload), oxidative stress, mitochondrial damage, and cell/mitochondria apoptosis happen. Therefore, Ca²⁺ overload has started to be deeply exploited as a new strategy for cancer therapy due to its high efficiency and satisfactory safety. This review aims to highlight the recent development of Ca²⁺-based nanomaterials (such as Ca₃(PO₄)₂, CaCO₃, CaO₂, CaH₂, CaS, and others) able to trigger intracellular Ca²⁺ overload and apoptosis in cancer therapy. The intracellular mechanisms of varied Ca²⁺-based nanomaterials and the different types of strategies to enhance Ca²⁺ overload are discussed in detail. Moreover, the design of more efficient Ca²⁺ overload-mediated cancer therapies is prospected mainly based on 1) the enhanced cellular uptake by surface modification and morphology optimization of nanomaterials, 2) the accelerated Ca²⁺ release from nanomaterials by increasing the intracellular H⁺ level and by photothermal effect, and 3) the overload maintenance by Ca²⁺ efflux inhibition, Ca²⁺ influx promotion, or promoting Ca²⁺ release from the endoplasmic reticulum.     

热电Ca3Co4O9薄膜的一致取向生长及其激光感生电压效应

利用脉冲激光沉积(PLD)法,在蓝宝石(0001)平衬底上成功制备了c轴一致取向的Ca3Co4O9薄膜。利用X射线衍射(XRD)分析测定了薄膜的相结构和生长取向。研究了不同衬底温度与不同原位氧压对Ca3Co4O9薄膜结晶质量与生长取向的影响,确定了最佳生长条件。利用这一条件在倾斜Al2O3(0001)衬底上制备了Ca3Co4O9薄膜。研究发现,当Ca3Co4O9薄膜被波长248nm,脉冲宽度20ns的脉冲激光照射时,在薄膜两端存在较大的激光感生热电电压(LITV)信号,峰值电压达到4.4V,其上升沿为36ns,半峰全宽(FWHM)为131ns。可以认为这种激光感生热电电压信号是由于Ca3Co4O9薄膜面内与面间泽贝克(Seebeck)系数张量的各向异性引起的。     

Cohesively Enhanced Conductivity and Adhesion of Flexible Silver Nanowire Networks by Biocompatible Polymer Sol–Gel Transition

Silver nanowire (AgNW) networks are a promising candidate to replace indium tin oxide (ITO) as transparent conductors. In this paper, a novel transparent composite conductor composed of AgNW/biocompatible alginate gel on a flexible polyethylene terephthalate (PET) substrate, with synchronously enhanced adhesion and reduced resistivity, is prepared without high‐temperature annealing. The sheet resistance of the flexible AgNW/PET film reduces from 300 to 50.3 Ohm sq^?1 at transmittance of 94%. The optical and electrical performance is superior to that obtained from the flexible ITO film on PET. Meanwhile, the sheet resistance does not show great change after tape test, suggesting a good adhesion of AgNW to the polymer substrate. Moreover, the AgNW composite film shows a good stability to resist long‐term storage, solvent damage, and ultrasonication. Finally, polymer solar cells employing the composite AgNW film as the electrode are realized, displaying an efficiency of 2.44%.     

高温烧结羟基磷灰石靶的细胞相容性

为研究高温烧结羟基磷灰石靶的细胞相容性,把纯度为99%的羟基磷灰石粉末压制成圆盘形靶,在氩气中在800℃高温下烧结成型。用X射线衍射仪和X射线光电子能谱仪对羟基磷灰石靶的结构组成进行检测。用四氮唑盐比色法对羟基磷灰石靶的细胞相容性进行检测。检测结果表明：纯度为99%的羟基磷灰石粉末在压制成型和800℃高温烧结的过程中化学组成没有发生变化,羟基磷灰石靶中的平均粒径为78.2nm、结晶度为89.4%、Ca/P比值为1.592,具有很好的细胞相容性。