碱蓬植物盐提取工艺优化及其矿物质元素测定

目的 优化碱蓬植物盐提取工艺,测定碱蓬植物盐矿物质元素和重金属元素含量。方法 采用超声-微波协同提取法,以碱蓬植物盐得率为指标,通过单因素和响应面实验设计优化提取工艺参数。采用原子吸收光谱法和原子荧光光谱法测定碱蓬植物盐中元素含量。结果 优化的工艺参数为微波功率205 W、微波功率126 W、提取时间9 min、液料比82 mL:g,植物盐平均得率为31.50%±1.92%。不同生长阶段的碱蓬植物盐中,矿物质元素含量均呈现Na＞K＞Mg＞Ca＞Fe＞Cu＞Se的趋势,重金属元素Pb、Hg含量低于GB 2762-2021要求,未检测出As、Cd元素。结论 优化的工艺能够有效指导碱蓬植物盐的提取,碱蓬植物盐低钠高钾,富含多种营养元素,作为营养保健盐具有一定推广价值。     

纳米相铁红粒子的液相制备

由０．２ｍｏｌ·Ｌ^－１Ｆｅ^３＋采用微波诱导加热制备了纳米尺寸的准立方形和纺锤形α－Ｆｅ_２Ｏ_３粒子,与常规加热方式比较微波加热制得的α－Ｆｅ_２Ｏ_３粒子粒径小且分布均匀,实验证明无机离子加 Ｈ^＋、ＯＨ^－和 Ｎａ^＋等的加入可明显加速反应速率．     

Fabrication and characterization of TiO2/short MWNTs with enhanced photocatalytic activity

TiO₂/short MWNTs nanocomposites were prepared by the sol–gel method using butyl titanate and short MWNTs as starting materials in the solvent of isopropyl alcohol. Their photocatalytic activity in the degradation of X-3B was studied. The effects of mass ratio of short MWNTs to butyl titanate, and heat-treatment temperature on the photoactivity of TiO₂/short MWNTs nanocomposites were discussed. For comparison purpose, other photocatalysts were also employed in the photodegradation experiment. Thermogravimetric–differential thermal analysis (TG–DTA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV–Vis absorption spectra were utilized to characterize the prepared photocatalysts. The results showed that the TiO₂/short MWNTs nanocomposites synthesized with 1% mass ratio of short MWNTs to butyl titanate had the best photoactivity.     

Microstructure evolution and bonding mechanisms of silica sol bonded coating at elevated temperatures

High emissivity coating plays a critical role in thermal protective system, which can radiate a large amount of aero-convective heat. Silica sol bonded MoSi₂-SiC-Al₂O₃ (S-MSA) coating was proved to be promising for mullite fibrous insulation. However, the bonding mechanisms of the coating at elevated temperatures are not clear. In this work, the S-MSA coatings were heat-treated at temperatures from 600 °C to 1500 °C to reveal the bonding mechanisms at elevated temperatures. The S-MSA coatings go through a relatively stable stage (600 °C–1000 °C), a crystallization stage (1100 °C–1200 °C), and a densification stage (1300 °C–1500 °C) at ever increasing temperatures. Results show that both the contact damage resistance and the bonding strength of the calcined coatings exhibit a decrease followed by an increase at elevated calcination temperatures, with the inflection point at 1200 °C, corresponding to the transition temperature of the bonding mechanisms from 600 °C to 1500 °C.     

基于深度学习的室内照明智能调节系统

为了实现室内照明的智能控制,根据室内人员实时位置进行跟踪式照明,通过人员覆盖区域完成自适应亮度调节,达到总体节能且局部照明舒适的目的。设计了基于光纤传感网络的智能照明系统,提出了基于深度学习的照明区块化设计与人员实时定位的照明调节算法。区块化设计将照明区域划分成多个等尺寸子区域,划分尺度由光源覆盖间距决定,实现对照明区域的离散处理。再通过状态采集模块对每个子区域进行照度量化分析,将检测结果作为卷积网络输入层的控制参数导入分析模型中。结合封闭体人员定位算法实现对照明子区域定位及照度调节。实验测试了100 m2照明范围内的四种典型情况,获得了各LED对测试位置的照度权值,并测试了不同高度对照度值的影响程度。区域内在x轴方向的人员定位精度最大误差为?96 cm,在y轴方向为91 cm,均小于预设照明区块的最小单元。文中算法在LED个数递增时,收敛时间略优于ANN算法,与对应LED体量的照明空间相比,收敛时间满足应用需求,验证了其具有大范围照明智能调节的能力。     

基于SQL Server数据库的人事管理系统的研究与开发

随着信息技术的飞速发展,信息化系统在企业管理中应用的普及,利用计算机实现人事管理势在必行。企业利用人事管理系统,使公司管理者和管理部门能够更科学、合理、公平地对企业人事进行管理。文章基于SQL Server数据库对人事管理系统进行研究与开发。     

La_(0.60)Sr_(0.40-x)K_xMnO_3系列材料的磁电阻效应

利用溶胶-凝胶法(sol-gel)制备了多晶类钙钛矿型稀土锰氧化物La0.60Sr0.40-xKxMnO3(x=0.00,0.15,0.20,0.30)。发现K+取代部分Sr2+后,可使样品的居里温度降至室温附近,并且使样品的室温磁电阻比替代前明显增大。在1.8T的磁场下,x=0.30的样品磁电阻峰值为21%,相应的峰值温度为304K。而母体La0.60Sr0.40MnO3的磁电阻峰值仅为6.4%,峰值温度为373K。可见K+离子替代使室温附近样品的庞磁电阻效应有了明显的改善。     

醛-亚胺-壳聚糖水凝胶的构筑及性能研究进展

动态亚胺键（又称席夫碱键）具有pH响应性、可逆性和生物活性等,因此,亚胺键交联构筑的水凝胶可能被赋予许多新的功能。壳聚糖是自然界中唯一的碱性多糖,分子链上丰富的氨基为醛-亚胺-壳聚糖（CSB）水凝胶的构筑提供了可能。近年来,CSB水凝胶的构筑和应用受到关注,其中,醛类交联分子的结构和交联点的设计成为研究热点之一。该文按照醛类交联分子的结构特点,对CSB水凝胶的构筑方法、机理以及自愈合性能、药物缓释性能、抗菌性能、荧光性能和导电性能等进行了综述,为构筑多功能壳聚糖水凝胶提供理论指导。设计合成生物相容性好、多功能醛类交联剂;提高CSB水凝胶的力学性能、自愈合性能和刺激响应性能,是CSB水凝胶的重要研究方向。     

The influence of temperature on the solubility limit of Ca in alumina

Dopants and impurities can adsorb to surfaces and grain boundaries in ceramics, influencing the sintering kinetics and grain boundary mobility during processing. Ca is a common impurity in alumina that promotes grain growth at concentrations below the solubility limit, in contrast to the commonly observed solute-drag effect. Knowledge of the Ca solubility limit at temperatures relevant to processing is important to control microstructural evolution. Here we report on the experimentally measured solubility limit of Ca in α-alumina at 1400 °C and 1500 °C from equilibrated and quenched samples using standardized wavelength dispersive spectroscopy to be 32 ± 3 ppm and 45 ± 3 ppm, respectively. Together with the previously measured Ca solubility limit at 1600 °C, the enthalpy (0.95 eV per Ca) and vibrational entropy (-7.35 × 10⁻⁴ eV K^-1 per Ca) of solution were determined. A negative vibrational entropy of solution indicates coulombic interactions between the Ca cations and charge compensating defects in α-alumina.