SIMULATIONS OF MECHANICAL BEHAVIOR OF POLYCRYSTALLINE COPPER WITH NANO-TWINS

Mechanical behavior and microstructure evolution of polycrystalline copper with nano-twins were investigated in the present work by finite element simulations. The fracture of grain boundaries are described by a cohesive interface constitutive model based on the strain gradient plasticity theory. A systematic study of the strength and ductility for different grain sizes and twin lamellae distributions is performed. The results show that the material strength and ductility strongly depend on the grain size and the distribution of twin lamellae microstructures in the polycrystalline copper.     

消癌平诱导人肺腺癌(ASTC-a-1)细胞内caspase-3活化的荧光光谱分析

采用CCK-8技术检测发现传统中药消癌平（XAP）对人肺腺癌（ASTC-a-1）细胞的增殖活性具有显著的抑制作用。利用共聚焦扫描荧光显微成像、荧光共振能量转移（FRET）及其受体光漂白技术证实了基于FRET技术构建的SCAT3质粒在ASTC-a-1细胞中的稳定表达。将消癌平加入细胞培养液中培育细胞,并在不同的时间检测活细胞内SCAT3的荧光发射光谱,从而监测细胞中caspase-3的活化状态。实验结果表明：(1)消癌平可以有效抑制人肺腺癌（ASTC-a-1）细胞的增殖活性并诱导细胞的死亡,消癌平对细胞的抑制作用具有剂量依赖性。(2)消癌平处理细胞72 h后,细胞内大量的SCAT3被切割,表明细胞内caspase-3的活化水平明显升高。(3)将含消癌平的细胞培养液与细胞共同培养24 h,然后采用没有消癌平的细胞培养液培养细胞48和72 h后,细胞内SCAT3的光谱没有明显改变,表明消癌平作用细胞24 h内没有显著激活细胞内的caspase-3。     

五种郁金无机元素比较及样品元素间相关性分析

中药含有丰富的无机元素,特别是人体必需的无机元素含量较高。在样品中加入混酸,再用微波消解技术消化样品,采用火焰原子吸收光谱法对五种不同品种郁金（温郁金、姜黄、广西莪术、蓬莪术和川郁金）所含有的八种具有重要生理功能的无机元素——钾、钙、钠、镁、锌、铁、铜和锰的含量进行了测定。结果显示郁金类中药材含有相近的元素成分,不同来源的品种在个别元素含量上存在差异。基于各样品所含无机元素采用聚类分析进行相关性分析,药典所收载四种郁金（温郁金、姜黄、广西莪术和蓬莪术）聚为一类,与非正品川郁金有所区别,该聚类结果与依据形态特征的传统分类学结果一致。测定结果可为郁金中无机元素与其药效的相关性提供科学依据。     

基于可见/近红外能量光谱的苹果褐腐病和水心鉴别

快速无损鉴别苹果内部品质的优劣是当前苹果行业亟待解决的一项重要课题.针对这一现状,提出了直接采用可见一近红外能量光谱对苹果褐腐病、水心鉴别的新方法,考察了不同判别分析方法对苹果类别判定的准确性.在能量光谱经MSC或者一阶导数处理后,分别采用了峰面积判别法(PADA)、主成分分析判别法(PCADA)、偏最小二乘判别法(PLSDA)建立判别模型.结果显示,三种方法对褐腐病苹果判别正确率都为100%;对水心苹果分别是79.2%,95.0%和96.7%;对正常苹果分别是88.6%,98.2%和98.8%.其中,PCADA和PLSDA明显优于PADA,而PLSDA总判别率最高,达到98.1%,其建模标准差RMSEC为0.449,预测标准差RMSEP为0.392,说明可见一近红外能量光谱结合化学计量学算法可以快速、无损鉴别苹果褐腐病和水心.     

垃圾填埋渗滤液溶解性有机物组分的光谱学特性研究

选取3个不同填埋年限的渗滤液样品,以Leenheer的分组方法为基础,采用XAD-8树脂将渗滤液中的溶解性有机物(DOM)按极性和电荷特性分为结构较为均一的不同组分,用荧光光谱和紫外光谱对其中3个组分进行分析。荧光光谱分析表明,填埋初期,疏水酸性组分(HOA)、疏水中性组分(HON)和亲水性组分(HIM)均以类蛋白物质为主,随着填埋年限增加,其分子复杂化程度增强;其中HOA组分分子量最大、复杂程度最高,同时芳烃化合物的含量也最高,HON居中,HIM组分最小。紫外光谱分析表明,HOA和HON组分芳香环上的取代基均以羰基、羧基、羟基为主;而HIM组分则以脂肪链为主,同时芳香烃化合物含量较低。研究结果表明,随着填埋年限的增加,三种组分的复杂化程度均呈上升趋势。     

蔬菜中硒总量及形态的氢化物发生-原子荧光光谱测定方法

采用氢化物发生原子荧光光谱法(HG-AFS)测定了几种蔬菜中的总硒含量,并测定了其中无机硒和有机硒的相对含量。实验优化了仪器测量参数,考察了载流盐酸和硼氢化钾浓度、样品介质盐酸浓度和残留硝酸浓度及干扰元素对测定的影响。结果表明：几种蔬菜中硒的含量都较低,而草菇的硒含量达到0.151 μg·g-1。此外,蔬菜中硒主要以有机硒的形态存在。方法的检出限为0.35 ng·g-1,加标回收率为97.6%～101%。实验方法操作简便、灵敏度高,结果令人满意。     

An Improvement to Conformer-Based Model for High-Accuracy Speech Feature Extraction and Learning

Owing to the loss of effective information and incomplete feature extraction caused by the convolution and pooling operations in a convolution subsampling network, the accuracy and speed of current speech processing architectures based on the conformer model are influenced because the shallow features of speech signals are not completely extracted. To solve these problems, in this study, we researched a method that used a capsule network to improve the accuracy of feature extraction in a conformer-based model, and then, we proposed a new end-to-end model architecture for speech recognition. First, to improve the accuracy of speech feature extraction, a capsule network with a dynamic routing mechanism was introduced into the conformer model; thus, the structural information in speech was preserved, and it was input to the conformer blocks via sequestered vectors; the learning ability of the conformed-based model was significantly enhanced using dynamic weight updating. Second, a residual network was added to the capsule blocks, thus, the mapping ability of our model was improved and the training difficulty was reduced. Furthermore, the bi-transformer model was adopted in the decoding network to promote the consistency of the hypotheses in different directions through bidirectional modeling. Finally, the effectiveness and robustness of the proposed model were verified against different types of recognition models by performing multiple sets of experiments. The experimental results demonstrated that our speech recognition model achieved a lower word error rate without a language model because of the higher accuracy of speech feature extraction and learning using our model architecture with a capsule network. Furthermore, our model architecture benefited from the advantage of the capsule network and the conformer encoder, and also has potential for other speech-related applications.     

Cloning,Expression, Purification,and Characterization of β-Galactosidase from Bifidobacterium longum and Bifidobacterium pseudocatenulatum

Expression and purification of β-galactosidases derived from Bifidobacterium provide a new resource for efficient lactose hydrolysis and lactose intolerance alleviation. Here, we cloned and expressed two β-galactosidases derived from Bifidobacterium. The optimal pH for BLGLB1 was 5.5, and the optimal temperature was 45 °C, at which the enzyme activity of BLGLB1 was higher than that of commercial enzyme E (300 ± 3.6 U/mg) under its optimal conditions, reaching 2200 ± 15 U/mg. The optimal pH and temperature for BPGLB1 were 6.0 and 45 °C, respectively, and the enzyme activity (0.58 ± 0.03 U/mg) under optimum conditions was significantly lower than that of BLGLB1. The structures of the two β-galactosidase were similar, with all known key sites conserved. When o-nitrophenyl-β-D-galactoside (oNPG) was used as an enzyme reaction substrate, the maximum reaction velocity (V_max) for BLGLB1 and BPGLB1 was 3700 ± 100 U/mg and 1.1 ± 0.1 U/mg, respectively. The kinetic constant (K_m) of BLGLB1 and BPGLB1 was 1.9 ± 0.1 and 1.3 ± 0.3 mmol/L, respectively. The respective catalytic constant (k_cat) of BLGLB1 and BPGLB1 was 1700 ± 40 s⁻¹ and 0.5 ± 0.02 s⁻¹, respectively; the respective k_cat/K_m value of BLGLB1 and BPGLB1 was 870 L/(mmol∙s) and 0.36 L/(mmol∙s), respectively. The K_m, k_cat and V_max values of BLGLB1 were superior to those of earlier reported β-galactosidase derived from Bifidobacterium. Overall, BLGLB1 has potential application in the food industry.     

Preparation of Silica Aerogel/Resin Composites and Their Application in Dental Restorative Materials

As the most advanced aerogel material, silica aerogel has had transformative industrial impacts. However, the use of silica aerogel is currently limited to the field of thermal insulation materials, so it is urgent to expand its application into other fields. In this work, silica aerogel/resin composites were successfully prepared by combining silica aerogel with a resin matrix for dental restoration. The applications of this material in the field of dental restoration, as well as its performance, are discussed in depth. It was demonstrated that, when the ratio of the resin matrix Bis-GMA to TEGDMA was 1:1, and the content of silica aerogel with 50 μm particle size was 12.5%, the composite achieved excellent mechanical properties. The flexural strength of the silica aerogel/resin composite reached 62.9546 MPa, which was more than five times that of the pure resin. Due to the presence of the silica aerogel, the composite also demonstrated outstanding antibacterial capabilities, meeting the demand for antimicrobial properties in dental materials. This work successfully investigated the prospect of using commercially available silica aerogels in dental restorative materials; we provide an easy method for using silica aerogels as dental restorative materials, as well as a reference for their application in the field of biomedical materials.     

金衢盆地加积型红土地球化学特征

金衢盆地广泛分布着不同类型的第四纪红土。通过X射线荧光光谱法（XRF）对金衢盆地的85个样品进行了测试。结果表明：（1）主量元素组成以SiO2、Fe2O3、Al2O3为主,K、Na、Ca、Mg等易溶组分的含量很低,TiO2含量的平均值高于UCC值;（2）MnO含量在网纹红土和均质红土的交界处明显聚集,推测与不同沉积物交界处理化性质突变有关;（3）在剖面上,SiO2、Fe2O3、AkO3等化学成分和硅铝率沿剖面变化的趋势,以及基岩和上覆沉积层的元素组成、化学风化指标和Ti／Zr的区别,均表明所研究的金衢盆地红土剖面具有较好的相似性,与典型的岩石风化壳存在明显差别。