新疆奇台和缅甸蒲甘硅化木的宝石学特征

采用常规宝石学测试方法及偏光显微镜、扫描电子显微镜、电子探针、X射线粉末衍射仪等测试手段,对中国新疆奇台及缅甸蒲甘的硅化木样品,从显微结构、宝石学及矿物学特征等方面进行测试与分析。结果表明,本次研究所测试的两地硅化木样品主要矿物组成均为石英(SiO2占总质量分数的90%以上),微晶-显微隐晶质结构,其他矿物的质量分数较低。通过对石英结晶度计算和扫描电子显微镜下石英颗粒形态特征观察,发现缅甸蒲甘硅化木样品的石英结晶度明显高于中国新疆奇台硅化木样品。此外,通过手标本观察、偏光显微镜及扫描电子显微镜下观察,发现新疆奇台硅化木样品中透明度较好的区域,石英颗粒呈放射状或为纤维状玉髓,颗粒较小;而透明度较差的区域,石英颗粒呈柱状、粒状等形态,颗粒之间结合不够紧密。缅甸蒲甘硅化木样品整体均不透明,石英颗粒呈粒状,粒度较大,尺寸在微米级别。     

丝绸材料的扫描电镜样品镀膜技术研究

纤维状结构、织态结构、成膜结构和粉末状结构等种类繁多的丝绸材料，其结构性能差异较大，为适应扫描电子显微镜成像对样品的要求，本文针对这些材料不同的形貌结构和性能进行分析，并探讨了相应材料的镀技术。     

扫描电子显微镜在经纱上浆研究中的应用

本文介绍扫描电子显微镜观察上浆经纱的新方法，它具有清晰度高，立体感强的优点，对衡量经纱上浆效果具有较高的实用价值。     

扫描电镜样品(卷烟配套用纸、填料)前处理方法讨论及扫描时最优参数的摸索

扫描电镜作为一种有效的显微结构分析工具,在造纸行业广泛利用。为了更好的配合造纸研究和工艺改进,摸索扫描电镜最佳工作参数尤为重要。本文以卷烟配套用纸、填料为例,讨论了扫描电镜样品(卷烟配套用纸、填料)前处理方法以及扫描时的最优参数。通过比较不同工作条件下的样品表面形貌,得出扫描最优加速电压为10KV;扫描工作距离的适当缩短有利于提高图像分辨率。     

扫描电镜在方便稀饭研制中的应用

方便稀饭的口感在很大程度上取决于成品的复水性，而成品的复水性与方便稀饭米粒内部淀粉结构密切相关。透彻了解淀粉结构从而对稀饭米粒组织结构进行有效修饰是生产可接受方便稀饭的基本前提，对改善食品品质具有极其重要的意义。本文采用扫描电子显微镜对方便稀饭加工过程中米粒的结构变化进行了观察，从理论方面对方便稀饭的复水性及口感问题作出了较合理的解释。     

扫描电镜测试条件的优化及造纸填料形貌分析

扫描电子显微镜作为形貌分析的观察手段,具有高效、灵敏的特点,制备样品简单,分辨率高,成像景深大,立体感强,直接观察样品的原始表面。通过选择仪器最佳工作参数,测试了四种常用造纸填料的微观形貌。     

提高氧化锆陶瓷笔珠书写带墨能力的研究

为了解决氧化锆陶瓷笔珠书写带墨能力差,初写断线的问题,本文采用了一种表面修饰技术,对抛光之后Ra≤7nm的氧化锆陶瓷笔珠进行表面处理,结果表明其书写带墨能力提高了15％左右,初写打滑现象得到有效避免。通过扫描电子显微镜(SEM)和原子力显微镜(AFM)对处理前、后的样品进行对比观察,发现表面修饰可以在笔珠表面形成提高带墨能力的显微结构。     

“金鳞石”(锂云母玉)的宝石学特征

采用常规宝石学测试,并结合扫描电子显微镜、偏光显微镜、傅里叶红外光谱仪、X射线能谱仪、X射线粉末衍射仪、激光拉曼光谱仪等大型仪器,对市场上出现的一种商业俗称“金鳞石”的宝石材料的宝石学特征、矿物组成、化学成分等进行了测试与分析。结果表明,“金鳞石”样品为锂云母玉,其折射率为1.55(点测),摩氏硬度为2~3,相对密度为2.83;红外光谱和拉曼光谱的测试结果表明样品与云母的图谱基本一致;扫描电子显微镜观察结果显示样品为矿物集合体,具有极完全解理,参差状断口,细粒鳞片变晶结构;X射线能谱结果显示样品主要含有Si、Al、K、F、O等;偏光显微镜、X射线粉末衍射分析结果均表明样品主要由锂云母和少量白云母组成,按照《GB/T 16552—2010珠宝玉石名称》相关规定,应定名为锂云母玉。长波紫外荧光下观察锂云母玉样品内部网格状裂隙内的荧光呈强蓝白色,与锂云母玉样品主体弱紫色荧光颜色不一致,显微镜下观察发现裂隙表面的光泽差异明显,伴有密集的气泡群,表明锂云母玉样品经过充填处理。     

扫描电镜在棉织物酶处理检测中的应用

利用扫描电子显微镜的特性,针对如何更快更准确地检测棉织物表面酶处理的性状问题,提出电子显微镜技术检测法。用扫描电子显微镜对处理过的牛仔布织物的表面进行扫描观察,从而判断织物在经生物酶处理后的整理效果,同时比较了几种不同厂家生产的中性纤维素酶对同种棉织物的作用效果。进一步探究了扫描电子显微镜的应用范围,也为今后纺织品的检测提供了良好方法。     

珊瑚成分结构特点研究（上）

文章通过红外光谱仪、激光诱导等离子体击穿光谱仪（LIBS）、环境扫描电子显微镜等大型仪器对珊瑚样品进行测试分析对比,确定样品的基本性质及成分、结构的特点。结果显示,珊瑚主要成分为方解石和烃类有机物,横切面同心状结构与放射状结构交替出现,方解石呈层状排列,底部有机物及无机物粒度均比样品顶部大。     

Morphological transitions of Bacillus subtilis in the presence of food-grade lipidic nanoemulsions

The present study aims to study the antibacterial activity of food-grade lipidic nanoemulsion (noncationized/cationized) against Bacillus subtilis (BS). Bactericidal activity was ascertained by studying the morphological transitions on BS using transmission electron microscopy (TEM), atomic force microscopy (AFM), and scanning electron microscopy (SEM). Morphological changes were witnessed by cell wall breakage, oozing out of cellular contents, loss of cell turgidity and contour. Furthermore, aggregation of cationic nanoemulsion (CaNM) was preferentially observed at apical side of BS construing comparatively more electrostatic attraction between electronegative apical side and CaNM. Resistance response of BS exhibited by apical cell-wall thickening was not able to protect the bacteria due to leakage of cellular content. AFM corroborated its importance in bacteriology, wherein the fragmented cell wall can be “piece-by-piece” identified and sutured back to its appropriate vacant places, thereby, completing the cell wall contour of the ghost cell. Such postmortem analysis of bacterial cell using AFM studies can throw light toward mechanism of cell fragmentation of bacterial cells. SEM study also demonstrated the deformed, fragmented, and amorphous nature of BS construing the bactericidal effect of prepared nanoemulsion.     

Interactions between milk proteins and exopolysaccharides produced by Lactococcus lactis observed by scanning electron microscopy

The interactions between exopolysaccharides produced by Lactococcus lactis ssp. cremoris JFR1 and dairy proteins (caseins and whey proteins) in fermented media (milk permeate and buttermilk) were observed using scanning electron microscopy. An immobilization technique by crosslinking was employed to bind the protein to the observation surface, so that a washing step could be performed to remove noninteracting material. The use of this novel technique allowed us, for the first time, to confirm that the exopolysaccharide molecules interact with dairy proteins. Exopolysaccharides appear as filament strands attached to the protein aggregates and to the bacterial cells. This new sample preparation technique proved to be very valuable for observing molecular interactions in fermented media.     

香蕉茎的化学成分及其微观形态分析

分析了香蕉茎的主要化学成分;与其他非木材纤维原料相比,香蕉茎的纤维素和综纤维素含量较高,木素含量低。此外,对其微观结构进行了光学显微镜（LM）和扫描电子显微镜（SEM）观察,结果显示,香蕉茎的纤维细长,并具有独特的纤维盘旋结构和薄膜结构。     

Microstructure and textural and viscoelastic properties of model processed cheese with different dry matter and fat in dry matter content

The aim of this work was to examine the effect of a different dry matter (DM) contents (35 and 45% wt/wt) and fat in DM contents (40 and 50% wt/wt) on the textural and viscoelastic properties and microstructure of model processed cheeses made from real ingredients regularly used in the dairy industry. A constant DM content and constant fat in DM content were kept throughout the whole study. Apart from the basic chemical parameters, textural and viscoelastic properties of the model samples were measured and scanning electron microscopy was carried out. With increasing DM content, the rigidity of the products increased and the size of the fat globules in the model samples of the processed cheeses decreased. With increasing fat in DM content, the rigidity of the processed cheeses decreased and the size of the fat globules increased.     

Influence of Water on Molecular and Morphological Structure of Various Starches and Starch Derivatives

In this study the influence of water on untreated, pregelatinised, and chemical modified starches was investigated. Because of their different botanical source, the starch products contain various quantities of amylose and amylopectin. The water vapour absorption capacity of the starches was studied by sorption/desorption and thermogravimetrical measurements. Higher absorption capacities were found for potato starch and for starches containing carboxymethyl and hydroxyethyl groups. Characteristic molecular differences found by Raman spectroscopy were evaluated for untreated and modified starches. To this end, the starch raw materials were classified into groups with similar pretreatments and properties based on cluster analysis. Additionally, the gelatinisation of starch‐water mixtures (gels, powders, and films) was continuously studied using temperature‐dependent Raman spectroscopy. In comparison with powder spectra, the Raman spectra of the starch films showed shifts in band positions in the range of the CH deformation and CH stretching modes. With the exceptions of high‐amylose maize starch and carboxymethylated starch, all starches form films. Starch films differ in their surface structures, water contact angles, and rates of water drop absorption, which might be caused by the different retrogradation properties. The swelling and shrinking behaviour of starch films was investigated at the morphological level by in situ environmental scanning electron microscopy (ESEM) experiments and evaluated by grey value analysis. Films of untreated starch show stronger swelling and shrinking than films of pregelatinised products.     

Antimicrobial effect of Magnolia officinalis extract against Staphylococcus aureus

BACKGROUND: The antimicrobial effect of Magnolia officinalis extract (MOE) against Staphylococcus aureus was investigated in a minced mutton system and the mechanisms of its antimicrobial activity were studied by light microscopy, transmission electron microscopy and scanning electron microscopy observations. RESULTS: MOE inoculation effectively inhibited the growth of S. aureus in minced mutton compared with that in control meat without MOE. The cell membrane of S. aureus treated with MOE showed structural disorganisation and cytoplasmic volume overflow. After 48 h of exposure to MOE, many S. aureus cells had completely collapsed. CONCLUSION: The antimicrobial mechanisms of MOE resulted mainly in cell membrane and wall damage, causing increased permeability of cell membranes or lysis of cell walls and loss of cellular constituents, impairment of structural components and changes in bacterial cell morphology. Copyright © 2011 Society of Chemical Industry     

Okra mucilage powder: a novel functional ingredient with antioxidant activity and antibacterial mode of action revealed by scanning and transmission electron microscopy

Okra mucilage powder (OMP) was firstly reported its antibacterial mode of action observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The reconstituted OMP or okra mucilage solution (OMS) with the concentration at 120 mg/mL was analysed for its total phenolic contents, total flavonoid contents and antioxidant activity reported as 11.33 ± 0.265 mg gallic acid/100 mL, 5.06 ± 0.197 mg catechin/100 mL and 176.18 ± 12.180 µmol Trolox equivalent/100 mL, respectively. The OMS exhibited strong antibacterial activities on Bacillus cereus, Staphylococcus aureus and Listeria monocytogenes with more than 3 log reduction from bacterial inoculum. Nonetheless, mode of action of OMS studied via TEM revealed that cells treated with OMS showed broken cell walls, cell membrane separation and intracellular content leakage. SEM photography revealed furrowed bacterial cell wall surface for this OMS-treated cells when compared with untreated cells. Overall, our data suggested that the reconstituted OMP offered the greatest functional properties as antioxidant properties and antibacterial activities, aiding to its future application as a potential novel functional ingredient with health-promoting application.     

奶粉中羟基磷灰石成分的检测

将奶粉溶于超纯水中,经超声、离心、真空冷冻干燥提取奶粉中无机成分富含物,再经X射线粉末衍射(Xray powder diffraction,XRD)和傅里叶红外光谱法对其进行定性鉴别分析;于空白奶粉样品中加入不同浓度的针状纳米羟基磷灰石标准品,经与样品相同处理后进行XRD分析,利用扫描电子显微镜(Scanning electrons microscopy, SEM)、透射电子显微镜—能谱仪(Transmission electron microscopy-energy spectrometer,TEM-EDS)对样品及加标样品中提取成分进行了形貌和纳米尺寸表征。结果表明,加标样品XRD检测中确定含有羟基磷灰石成分,电镜下能观察到纳米尺寸的针状羟基磷灰石,因此验证了此方法检测纳米羟基磷灰石的可行性;5种样品中1种样品含有羟基磷灰石,并含有未知结构的类似于球状的纳米成分(元素组成为碳、氧、磷、氯),3种样品含有晶体状的方解石,1种样品不含有晶体状羟基磷灰石。     

Investigation of the microstructure of milk protein concentrate powders during rehydration: Alterations during storage

The aim of this work was to use scanning electron microscopy to investigate the microstructure of rehydrated milk protein concentrate powder (MPC) particles. A sample preparation method for scanning electron microscopy analysis of rehydrated MPC particles is described and used to characterize the time course of dissolution and the effects of prior storage on the dissolution process. The results show that a combination of different types of interactions (e.g., bridges, direct contact) between casein micelles results in a porous, gel-like structure that restrains the dispersion of individual micelles into the surrounding liquid phase without preventing water penetration and solubilization of nonmicellar components. During storage of the powder, increased interactions occur between and within micelles, leading to compaction of micelles and the formation of a monolayer skin of casein micelles packed close together, the combination of which are proposed to be responsible for the slow dissolution of stored MPC powders.