Structure and magnetic properties of Ca14MnP11

The compound Ca₁₄MnP₁₁ crystallizes in the Ca₁₄AlSb₁₁ structure type with the tetragonal space group I4₁/acd (Z=8) and lattice parameters of , c=20.7565(9) at 90 K. The structure consists of MnP₄⁹⁻ tetrahedron, P₃⁷⁻ trimer, 4 P³⁻ isolated anions and 14 Ca²⁺ cations. Similar to other compounds of this structure type containing phosphorous, the P₃⁷⁻ trimer has a central P atom that is best modeled in the structure as being equally split between two sites. In addition, there is no additional distortion of the manganese-containing tetrahedron compared with the main group analog, Ca₁₄GaP₁₁, suggesting that the Mn oxidation state is Mn²⁺. Temperature-dependent magnetic susceptibility shows that the compound is paramagnetic over the entire temperature range measured (2-300 K). The data can be fit with a modified Curie-Weiss law and provide an effective magnetic moment of 5.80 (2) B.M. with a Weiss constant of −2.13(2) K and . This moment is significantly higher than those measured for any of the Mn-containing analogs and is consistent with Mn²⁺. This result will be discussed in light of the electron counting scheme for Mn compounds of the Ca₁₄AlSb₁₁ structure-type.     

Perfluoro-1,3,5-tris(p-oligophenyl)benzenes: Amorphous Electron-Transport Materials with High-Glass-Transition Temperature and High Electron Mobility

Perfluoro-1,3,5-tris(p-quaterphenyl)benzene (PF-13Y) and perfluoro-1,3,5-tris(p-quinquephenyl)benzene (PF-16Y) have been synthesized and characterized. They showed higher glass transition temperatures compared with perfluoro-1,3,5-tris(p-terphenyl)benzene (PF-10Y). Organic light-emitting diodes were fabricated using these materials as the electron-transport layers. PF-13Y and -16Y are better electron transporters than PF-10Y. The electron mobilities of PF-10Y and Alq₃ were measured by the time-of-flight technique. PF-10Y showed higher electron mobilities (10⁻⁴ cm²/V s) and weaker electric field dependence compared with Alq₃.     

Kinetics parameters in Mg2SiO4:Tb thermoluminescent material

This paper reports a first approach on the kinetics parameters of terbium-activated magnesium orthosilicate using various methods. A deconvolution has also used for taking into account a more complex glow-curve structure.

---

Zusammenfassung Mittels verschiedener Methoden werden in erster Näherung die kinetischen Parameter von terbiumaktiviertem Magnesiumorthosilikat ermittelt Zur Berücksichtigung einer komplexeren Thermolumineszenzkurve wurde auch eine Dekonvolution angewendet.

     

左手材料阶跃型光纤的模场特性

从Maxwell方程组出发,讨论纤芯为左手材料,包层为右手材料阶跃型光纤,推导了矢量解的场方程.经过数学计算,求得了左手材料阶跃型光纤矢量解的特征方程.根据矢量模的分类,找到了TE模、TM模、HE模和EH模的特征方程.根据各模的特征方程,并且与右手材料光纤相关的特征方程,在靠近截止和远离截止两种情况下进行了比较,得到了左手材料光纤的某些奇异特性.     

透极远红外光学材料制备及性能研究

在一定的温度、压力等条件下,采用有机材料(聚四氟乙烯)和无机晶体(KBr、CsI),通过热合技术研制出样品几何尺寸为Φ20mm×3-5mm、透射波段分别为15-38μm(PE-KBr)和15-60μm(PE-CsI)的透极远红外复合光学材料。抗腐蚀性能测试结果表明,材料耐强酸、强碱及部分有机溶剂。机械性能分析表明材料在小于115℃范围内可安全使用。极远红外透过率测试结果表明,在1-15μm波段,平均透过率小于15%,15-38μm和15-60μm极远红外波段,平均透过率大于50%,并对影响材料透过率的因素进行了分析。     

两类单负材料组成的一维半无限光子晶体反射谱

运用传输矩阵方法和Bloch定理计算了两类单负材料组成的一维半无限光子晶体反射谱,与有限多层结构通带中振荡的反射谱相比,半无限结构的反射谱曲线是光滑的,是有限周期结构反射谱振幅取平均的结果,可用来估计通带中的反射率.研究半无限结构的反射谱,有利于分析带隙的位置和宽度,结果表明,由两类单负材料组成的光子晶体中,不仅存在零有效位相带隙,还存在角度带隙,尤其发现高频处的Bragg带隙也是一个全方位带隙.     

Assessment of Chemical Composition and Anti-Penicillium Activity of Vapours of Essential Oils from Abies Alba and Two Melaleuca Species in Food Model Systems

The possibilities of the practical utilization of essential oils (EOs) from various plant species in the food industry have attracted the attention of the scientific community. Following our previous studies, the antifungal activities of three further commercial EOs, Melaleuca armillaris subsp. armillaris (rosalina; REO), Melaleuca quinquenervia (niaouli; NEO), and Abies alba (fir; FEO), were evaluated in the present research in respect to their chemical profiles, over four different concentrations, 62.5 μL/L, 125 μL/L, 250 μL/L, and 500 μL/L. The findings revealed that the major compounds of REO, NEO, and FEO were linalool (47.5%), 1,8-cineole (40.8%), and α-pinene (25.2%), respectively. In vitro antifungal determinations showed that the inhibition zones of a Penicillium spp. mycelial growth ranged from no inhibitory effectiveness (00.00 ± 00.00 mm) to 16.00 ± 1.00 mm, indicating a very strong antifungal activity which was detected against P. citrinum after the highest REO concentration exposure. Furthermore, the in situ antifungal efficacy of all EOs investigated was shown to be dose-dependent. In this sense, we have found that the highest concentration (500 µL/L) of REO, NEO, and FEO significantly reduced (p < 0.05) the growth of all Penicillium strains inoculated on the bread, carrot, and potato models. These results indicate that the investigated EOs may be promising innovative agents in order to extend the shelf life of different types of food products, such as bread, carrot and potato.     

左手材料设计及透明现象研究进展

左手材料具有负的介电常数, 磁导率和折射率,它与电磁波相互作用的规律与传统材料有本质的区别.首先讨论了金属线点阵结构实现负介电常数和开口谐振环点阵结构实现负磁导率的内在机理,综述了目前实现左手材料的设计与制备方法,讨论了左手材料研究中能量如何定义以满足守恒律, 左手材料的宏观等效参数的确定,以及影响左手材料负折射相对频带带宽的因素。最后对左手材料在光子隧道效应和电磁波透明方面的应用进行了介绍,重点讨论了利用力学中的``中性夹杂'概念对电磁波透明的设计.论文还探讨了声波左手材料的概念和物理意义,介绍了用声波左手材料实现声波透明的方法.      

A Novel Gelatin-Based Sustained-Release Molluscicide for Control of the Invasive Agricultural Pest and Disease Vector Pomacea canaliculata

Pomacea canaliculata, one of the 100 most destructive invasive species in the world, and it is an important intermediate host of Angiostrongylus cantonensis. The molluscicides in current use are an effective method for controlling snails. However, most molluscicides have no slow-release effect and are toxic to nontarget organisms. Thus, these molluscicides cannot be used on a large scale to effectively act on snails. In this study, gelatin, a safe and nontoxic substance, was combined with sustained-release molluscicide and was found to reduce the toxicity of niclosamide to nontarget organisms. We assessed the effects of gelatin and molluscicide in controlling P. canaliculata snails and eggs. The results demonstrated that the niclosamide retention time with 1.0% and 1.5% gelatin sustained-release agents reached 20 days. Additionally, the mortality rate of P. canaliculata and their eggs increased as the concentration of the niclosamide sustained-release agents increased. The adult mortality rate of P. canaliculata reached 50% after the snails were exposed to gelatin with 0.1 mg/L niclosamide for 48 h. The hatching rate of P. canaliculata was only 28.5% of the normal group after the treatment was applied. The sustained-release molluscicide at this concentration was less toxic to zebrafish, which means that this molluscicide can increase the safety of niclosamide to control P. canaliculata in aquatic environments. In this study, we explored the safety of using niclosamide sustained-release agents with gelatin against P. canaliculata. The results suggest that gelatin is an ideal sustained-release agent that can provide a foundation for subsequent improvements in control of P. canaliculata.     

双"单电桥"法测量低电阻中的实用技巧例举

主要介绍了双"单电桥"法测量低电阻的基本原理与双"单电桥"法测量低电阻的几种实用技巧.