The optimization of silica gel synthesis from chemical bottle waste using response surface methodology

To reduce the amount of hazardous chemical bottle waste in the environment, we report the optimization research of silica extraction in chemical bottle waste into silica gel. Alkali fusion and sol–gel process were utilised to prepare silica gel effectively. The alkali fusion process was carried out by adding sodium hydroxide to produce sodium silicate. Afterwards, silica gel was prepared by the sol–gel method using hydrochloric acid. Box-Behnken Design (BBD) was applied to Optimisation factors the poptimiseactors affecting the silica recovery. The factors that optimised mass ratio, particle size, and temperature. The optimum recovery of silica gel was obtained by SiO₂: NaOH mass ratio of 1:3, the particle size of 63–74 µm, and a temperature of 800 °C. The purity of silica gel optimum is 63.74% characterised using X-ray fluorescence. The structure of silica gel is the appearance of amorphous peaks at 2θ 20-30° characterised using an x-ray diffractogram. The silica gel surface was characterises using scanning electron microscopy-energy dispersive x-ray. It showed an irregular surface and characteristic showed that silica gel had a radius of 15.74 nm and a specific surface area of 297.08 m².     

Syntheses of macrocyclic bisbibenzyls on solid support

We describe a route for the polymer supported total synthesis of the cyclic bisbibenzyls of the isoplagiochin type found in liverworts. TentaGel^® resins were used as solid support for a sequence involving Suzuki, Wittig and hydrogenation protocols. The polymer linked intermediates could be characterized by HR-MAS NMR. This route is to be extended to the synthesis of small libraries of differently halogenated derivatives.     

Synthesis, crystal structure and magnetic property of a new nickel selenite chloride: Ni5(SeO3)4Cl2

The new nickel selenite chloride, Ni₅(SeO₃)₄Cl₂, was obtained by high-temperature solid state reaction of NiCl₂, Ni₂O₃ and SeO₂ in a 1:2:4 molar ratio at 700 °C in an evacuated quartz tube. Its structure was established by single-crystal X-ray diffraction. Ni₅(SeO₃)₄Cl₂ crystallizes in the triclinic system, space group P-1 (No. 2) with cell parameters of a=8.076(2), b=9.288(2), c=9.376(2) Å, α=101.97(3), β=105.60(3), γ=91.83(3)° and Z=2. All nickel(II) ions in Ni₅(SeO₃)₄Cl₂ are octahedrally coordinated by selenite oxygens or/and chloride anions (([Ni(1)O₅Cl], [Ni(2)O₄Cl₂], [Ni(3)O₅Cl], [Ni(4)O₆] and [Ni(5)O₄Cl]). The structure of the title compound features a condensed three-dimensional (3D) network built by Ni(II) ions interconnected by SeO₃²⁻ anions as well as Cl⁻ anions. Magnetic property measurements show strong antiferromagnetic interaction between nickel(II) ions.     

Analysis of organic compounds in environmental samples by headspace solid phase microextraction

The analysis of samples contaminated by organic compounds is an important aspect of environmental monitoring. Because of the complex nature of these samples, isolating target organic compounds from their matrices is a major challenge. A new isolation technique, solid phase microextraction, or SPME, has recently been developed in our laboratory. This technique combines the extraction and concentration processes into one step; a fused silica fiber coated with a polymer is used to extract analytes and transfer them into a GC injector for thermal desorption and analysis. It is simple, rapid, inexpensive, completely solvent-free, and easily automated. To minimize matrix interferences in environmental samples, SPME can be used to extract analytes from the headspace above the sample. The combination of headspace sampling with SPME separates volatile and semi-volatile analytes from non-volatile compounds, thus greatly reducing the interferences from non-target compounds. This paper reports the use of headspace SPME to isolate volatile organic compounds from various matrices such as water, sand, clay, and sludge. By use of the technique, benzene, toluene, ethyl-benzene, and xylene isomers (commonly known as BTEX), and volatile chlorinated compounds can be efficiently isolated from various matrices with good precision and low limits of detection. This study has found that the sensitivity of the method can be greatly improved by the addition of salt to water samples, water to soil samples, or by heating. Headspace SPME can also be used to sample semi-volatile compounds, such as PAHs, from complex matrices.     

大功率固态调制器的仿真研究

 设计了大功率固态调制器的新型固态脉冲开关模块。通过分析电力电子仿真软件Saber中绝缘栅双极晶体管(IGBT)物理模型的概念和等效电路,结合实验数据建立了IXDH20N120型IGBT的模型,研究了Saber环境下,不同参数条件和拓扑结构对调制器电路输出特性的影响。仿真结果表明：动态均压网络在有效地保护开关的同时,可以减少IGBT的开关损耗;电路中器件离散性与系统分布参数会造成调制器输出波形质量下降,效率降低。并对调制器在负载打火情况下,因严重不均流而损坏器件故障的机理作了分析,实验证明仿真结果和分析与实际相符。     

多目标多光谱辐射高速高温计的研制

固体火箭羽焰是一种特殊的火焰,固体火箭发动机喷管羽流沿径向和轴向的温度是研究固体推进剂燃烧状况和发动机燃烧流场的基本参数。针对固体火箭发动机尾喷焰温度及其空间分布测量的需要,继1999年采用多光谱辐射测温方法和技术实现航天某型号固体火箭发动机测量后,研制了新型的多目标多光谱辐射高速高温计用于固体火箭发动机地面搭载试验。仪器使用组合棱镜和光电二极管阵列实现目标0.4~1.1μm光谱的热辐射测量,在主光路设计中首次使用光纤技术,实现一台仪器同时测量空间分布6个目标点的温度和发射率,每个点的空间位置由光阑上的通光孔精确确定,且每个目标测点均有8个工作光谱,研制的同步高速数据采集系统完成48个测量通道的数据同步时间小于10 ns。     

不同负荷下餐厨垃圾与水稻秸秆共消化厌氧产氢研究

进料负荷对餐厨垃圾与水稻秸秆混合厌氧发酵产氢过程有重要影响. 以进料负荷为影响因子, 设置温度均为55℃的餐厨垃圾与水稻秸秆混合厌氧发酵产氢实验, 其中进料负荷(以VS计)分别设置为(A)5kg?m-3?d-1、(B)10kg?m-3?d-1、(C)15kg?m-3?d-1, 分析厌氧产氢过程中产气量、产氢速率、pH、VFAs、氨氮、SCOD等参数的变化. 实验结果表明: B组发酵底物产气量最大, 为8664mL, 产氢速率也最大, 为748.3mL?h-1, 反应过程中pH始终维持在5.5±0.1内, 是厌氧产氢的最佳范围. 实验结束时, 各组VFAs、氨氮浓度分别为7292.46、8248.35、8558.24mg?L-1和544.48、754.31、1458.33mg?L-1. 同时各组SCOD浓度变化趋势相似. 在研究范围的最佳进料负荷下, 进行回流比分别为10%、30%、50%的实验, 结果显示30%回流比的产氢量最大, 为56039mL, 同时运行过程中系统稳定性较好. 综上所述, 进料负荷为10kg?m-3?d-1, 30%回流比的餐厨垃圾与水稻秸秆混合厌氧发酵产氢时, 微生物活性较好, 能够产生更多的氢气. 这一结果可为餐厨垃圾资源化提供参考依据.     

Markierung von Humanserumalbumin mit 131J durch elektrochemische Oxydation von Jodid zum Jod

Es wird über eine Methode und deren optimale Bedingungen berichtet, die eine schnelle, schonende und fernbediente Markierung von Humanserumalbumin mit ¹³¹ J gestattet. Die Markierungsausbeuten, bezogen auf das eingesetzte Jod, sind gut reproduzierbar und liegen bei über 90%.     

ICP光源的激光烧蚀固体样品引入方法进展

根据近几年来国内外的有关文献,叙述了ICP光源的激光烧蚀固体进样方法的研究进展及其在物质成分分析中的应用。着重阐述了激光输出特性(输出波长、脉冲宽度、重复频率、能量密度)和环境气氛(氦气、氩气)对样品烧蚀过程的影响,讨论了激光烧蚀室、气溶胶传输管道及样品引入改进装置在蒸发物质被传输到ICP光源过程中的作用。获得较小而均匀的气溶胶颗粒和稳定高效地将烧蚀物质输送到ICP是完善激光烧蚀固体进样技术的关键环节,元素分馏效应及蒸发物沉积是影响分析性能的重要因素。作为实际例子,也讨论了激光烧蚀固体进样电感耦合等离子体发射光谱法/质谱法在金属、玻璃、有机物及其他样品分析方面的应用,对分析方法的准确度、精密度、检出限和灵敏度进行了简要论述。     

在有限空间内生成的晶格高度取向的ZnO纳米颗粒

应用固态反应的方法,在260和300 oC空气中分别热分解层状锌油酸固体得到氧化锌纳米颗粒/团簇．高分辨透射电子显微镜和选区电子衍射表明,这种团簇是带有各种缺陷的单晶．光致发光激发光谱表明这两个样品在272和366 nm有两个频段．前者可能是由于不到200个氧化锌分子组成的团簇从价带到导带的电子转移引起的．