Detection of beeswax adulterations using concentration guide‐values

The concentrations of 102 chemical compounds (saturated and unsaturated hydrocarbons, palmitates, total and free acids, total hydroxyacids, total and free alcohols, acidic monoesters and monoesterified 1,2,3‐propanetriols) have been determined by GC/FID on white and yellow comb beeswax of Apis mellifera from different regions of Spain. Guide‐value ranges are proposed for its characterization and to discriminate adulterated foundation beeswax sheets. The concentrations of many compounds resulted to be statistically different for white and yellow beeswaxes, while the observation of concentrations out of normal in some marketed foundation beeswax sheets suggested their adulteration. However, the measurement of anomalous concentrations in foundation beeswax sheets did not imply necessarily their rejection by the bees.     

竹子状MnxW1-xS2纳米管制备与表征

以WS2为前驱体,用剥离-插层-水热掺杂这一种新的技术方法制备了竹子状MnxW1-xS2纳米管.在常温下将前驱体WS2用正丁基锂处理15 d,经正已烷冲洗6次后,在60 ℃,真空(0.01 Pa)干燥12 h,将适量样品置于装有MnCl2水溶液的高压反应釜中,然后将高压反应釜升温至180 ℃,并保温72 h,自然冷却,过滤干燥后即得所需产物.采用X射线衍射、透射电子显微镜、高分辨透射电子显微镜和X射线能量散射谱对样品进行了表征.结果表明:样品的形貌为具有尖头和节的竹子状纳米管;竹子状纳米管的尖端、管壁和节部具有清晰的层状结构,层间距离基本相等;竹子状纳米管的化学组成为Mn,W和S.     

氧化铁对硫铝酸钙矿物形成的影响

借助化学分析方法、X射线衍射、差示扫描量热法等测试手段研究了Fe2O3对无水硫铝酸钙矿物(C4A3S)形成过程的影响.研究表明:掺杂Fe2O3可促进熟料中游离氧化钙(f-CaO)的吸收,增加液相量,改善C4A3-S矿物生料的易烧性;不掺杂Fe2O3的矿物生料,C4A3-S单矿物在850℃以下几乎不生成,在1 000℃开始大量生成,在1 300℃达到最高值;掺杂1?2O3的试样中C4A3S含量与不掺杂试样在同温度下达到最大值,但绝对含量有一定幅度的下降;掺杂3%及5?2O3的试样中C4A3S含量在1 350℃达到最大值,达到最大值的时间比原来延迟0.5h,并且绝对含量有较大幅度的下降;掺杂Fe2O3的试样在1 200℃至1400℃时,Fe3 和C4A3-S中的Al3 发生置换,使Fe3 固熔到C4A3-S中形成固熔体C4(A0.95F0.05)6O12(SO4).     

Mn2+、Nb5+共掺BaTiO3陶瓷的制备及压电性能的研究

本文采用改进的固相反应法,制备了施主杂质Nb5 和受主杂质Mn2 共掺的BaTiO3陶瓷。按不同Nb5 、Mn2 的掺杂量,分别在1180℃、1210℃、1250℃、1280℃温度下煅烧。实验结果表明:当烧结温度为1250℃、掺杂量为0.05mol%时,制得的试样性能较好。     

湿度对CR-39固体核径迹探测器测量^220Rn／^222Rn水平的影响研究

在可调控温度、湿度及氡浓度的南华大学氡实验室对不同的湿度条件下CR-39固体核径迹探测器测量^220Rn、^222Rn的探测效率进行了测定,分析了湿度对CR-39固体核径迹探测器测量^220Rn、^222Rn探测效率的影响．实验结果表明：相对湿度在35％-95％范围内,当湿度为50％左右时,CR-39固体核径迹探测器测^222Rn,探测效率最高,标准偏差为2．0％;相对湿度在30％-100％范围内,当湿度为75％时,CR-39固体核径迹探测器测^220Rn的探测效率最低,标准偏差达到78．4％．     

Single particle tracking of fluorescent nanodiamonds in cells and organisms

Ever since the discovery of fullerenes in 1985, nanocarbon has demonstrated a wide range of applications in various areas of science and engineering. Compared with metal, oxide, and semiconductor nanoparticles, the carbon-based nanomaterials have distinct advantages in both biotechnological and biomedical applications due to their inherent biocompatibility. Fluorescent nanodiamond (FND) joined the nanocarbon family in 2005. It was initially developed as a contrast agent for bioimaging because it can emit bright red photoluminescence from negatively charged nitrogen-vacancy centers built in the diamond matrix. A notable application of this technology is to study the cytoplasmic dynamics of living cells by tracking single bioconjugated FNDs in intracellular medium. This article provides a critical review on recent advances and developments of such single particle tracking (SPT) research. It summarizes SPT and related studies of FNDs in cells (such as cancer cell lines) and organisms (including zebrafish embryos, fruit fly embryos, whole nematodes, and mice) using assorted imaging techniques.     

空间辐照环境下的FPGA可靠性设计技术

为了使基于SRAM结构的FPGA系统能够在空间辐照环境下稳定、安全、可靠地运行,FPGA软件的高可靠性设计便显得尤为重要。本文分析了空间辐照条件下FPGA发生故障的原因和机理,并结合实际设计的空间载荷项目,着重从软件方面提出了防范和解决的措施和方案。最后通过仿真和环境实验,验证了设计方案的可行性。     

抗震钨丝的现状与展望

叙述了抗震钨丝的掺杂机理和制备工艺，指出只有掺入K、Si和Al，才能获得良好的抗震性能。文章还介绍了国内外生产现状，并对抗震钨丝的发展方向提出了新的见解。     

How meaty? Detection and quantification of adulterants,foreign proteins and food additives in meat products

The worldwide consumption of meat is increasing, especially in developing countries. Many studies have correlated a diet characterised by high intake of processed red meats with a risk of colorectal cancer, stroke, coronary heart diseases and diabetes. Moreover, the quality and safety of meat products may be compromised by several admitted and not admitted procedures (i.e. addition of food additives and/or foreign proteins). For these reasons, the topic ‘meat products’ quality and safety’ has gained much in importance during last few years. In this review, the recent advances in the field of analytical methods for the evaluation of meat adulteration due to the addition of foreign proteins and food additives are reported, compared and critically evaluated. Moreover, the most representative monitoring practices, developed worldwide, related to meats adulteration are described and discussed.