Evaluation of the brain pH using a phosphorus magnetic resonance spectroscopy technique – a comparison of women and men

The aim of this study was to determine the reference value of pH in healthy women and men using the phosphorus magnetic resonance spectroscopy technique. The brains of 65 young volunteers were examined. The intracellular pH was calculated in the group of women and the group of men. In both groups, the average pH was slightly alkaline (respectively 7.10?±?0.08 and 7.08?±?0.12). No statistically significant sex difference in brain pH was found. Thus, in case if this method is used to estimate possible brain pathology in the young population, it is not needed to take the gender factor into consideration.     

顺序输送混油过程的二维数值分析

采用二维对流扩散模型对成品油顺序输送中的混油问题进行了数值模拟研究,运用目前求解对流扩散方程比较有效的两步法,对层流态和湍流态顺序输送的混油段流动分别进行了数值计算,分析了层流态和湍流态下的顺序输送规律,表明湍流态输送比层流态输送的混油量要小,并得到了混油截面平均浓度随时间的变化特点,以及湍流扩散系数对混油浓度的影响规律.     

激波/边界层相互作用诱导的激波风洞气体污染问题

应用多组分NS方程和频散可控耗散格式(DCD)计算了爆轰驱动激波风洞中反射激波/ 边界层/接触面的相互作用过程,分析了驱动气体与试验气体在壁面射流作用下的掺混机制及 其对风洞试验时间的影响. 为了延长风洞的试验时间,提出在风洞贮室内增设环形隔板, 以隔离壁面射流,延长风洞试验时间的方法. 计算结果表明：环形隔板确实可以限制驱动气 体与试验气体的过早掺混,显著增加激波风洞的有效试验时间.     

Phosphorus Dendrimers: Nano-objects for Nanosciences

Summary: The influence of the size (the generation) of phosphorus dendrimers on their properties is discussed in three main fields of applications: catalysis, new materials, and biology. Typical examples are given to illustrate these three fields: Knoevenagel condensation for catalysis, elaboration of highly sensitive DNA chips for materials, transfection experiments, and anti-prion activity for biology.     

Method Validation for Determination of Thallium by Inductively Coupled Plasma Mass Spectrometry and Monitoring of Various Foods in South Korea

Thallium (Tl) is a rare element and one of the most harmful metals. This study validated an analytical method for determining Tl in foods by inductively coupled plasma mass spectrometry (ICP-MS) based on food matrices and calories. For six representative foods, the method’s correlation coefficient (R²) was above 0.999, and the method limit of detection (MLOD) was 0.0070–0.0498 μg kg⁻¹, with accuracy ranging from 82.06% to 119.81% and precision within 10%. We investigated 304 various foods in the South Korean market, including agricultural, fishery, livestock, and processed foods. Tl above the MLOD level was detected in 148 samples and was less than 10 μg kg⁻¹ in 98% of the samples. Comparing the Tl concentrations among food groups revealed that fisheries and animal products had higher Tl contents than cereals and vegetables. Tl exposure via food intake did not exceed the health guidance level.     

手机数码比色法测定土壤中总磷含量

基于在酸性介质中,磷酸二氢钾(KH2PO4)与钼酸钠及抗坏血酸作用,生成蓝色的络合物,溶液的颜色随着KH2PO4浓度的增加而逐渐变浅,并呈现一定颜色梯度的原理,提出了使用手机数码比色法测定土壤中总磷含量的分析新方法。方法的相对标准偏差(RSD)为1.2%,对样品进行加标回收实验,加标回收率在102%¹03%。方法方便快捷,成本低,适合现场分析,是一种农民自行测定土壤中总磷含量的新方法。     

粉末压片X射线荧光光谱法测定铌铁合金中 铁、铌、硅、铝、磷

为提高铌铁合金检验效率,替代繁琐的化学湿法分析,采用粉末压片制样,利用X荧光光谱法对铌铁合金中Fe、Nb、Si、Al、P 5种主要成分进行测定。选用定值过的生产样品作为内控标准样品,主要研究制样细节对分析结果的影响,确认合适的试样粒度和压片参数,通过曲线拟合建立校准曲线。测定结果与化学湿法和电感耦合等离子体原子发射光谱法测定结果比较,各组分精密度相对标准偏差为0.48%～1.9%,准确度满足国标分析要求。     

Sn(II)/PN@AC catalysts: synthesis,physical-chemical characterization,and applications

In this study, the novel tin-based catalysts (Sn(II)/PN@AC) were prepared using the phosphorus and nitrogen dual-modified activated carbon as support and SnCl₂ as active compounds, as well as then evaluated in acetylene hydrochlorination. Under the reaction temperature of 180 °C and an acetylene gas hourly space velocity (GHSV-C₂H₂) of 30 h^–1, the 15%Sn(II)/PN@AC-550 showed the initial acetylene conversion of 100% and vinyl chloride selectivity over 98.5%. Additionally, the deactivation rate of 15%Sn(II)/PN@AC-550 reached 0.47% h^–1, which was lower than that of 15%Sn(II)/AC-550 (1.02% h^–1), suggesting that PN@AC-550 as novel support can retarded the deactivation of Sn(II)/AC-550 catalysts during acetylene hydrochlorination. Based on the catalytic tests and characterization results (XRD, Raman, BET surface area, TEM, C₂H₂-TPD, H₂-TPR, XPS, FT-IR, TGA, and ICP), it demonstrated that PN@AC-550 as support could effectively improve the dispersion of tin species, retard the formation of coke deposition, lessen the oxidation of SnCl₂ during the preparation process, as well as relatively inhibit the leach of tin species during the reaction. By combing the FTIR results and Rideal–Eley mechanism, we proposed that that HSnCl₃ was transition state of SnCl₂ in catalysis acetylene hydrochlorination and then adsorbed the acetylene to produce the vinyl chloride.